Typical recovery from NEC if medical, non-surgical treatment succeeds, includes 10–14 days or more without oral intake and then demonstrated ability to resume feedings and gain weight. Recovery from NEC alone may be compromised by co-morbid conditions that frequently accompany prematurity. Long-term complications of medical NEC include bowel obstruction and anemia.

In the United States it caused 355 deaths per 100,000 live births in 2013, down from 484 per 100,000 live births in 2009. Rates of death were almost three times higher for the black populations than for the white populations.

Overall, about 70-80% of infants who develop NEC survive. Medical management of NEC shows an increased chance of survival compared to surgical management. Despite a significant mortality risk, long-term prognosis for infants undergoing NEC surgery is improving, with survival rates of 70–80%. "Surgical NEC" survivors are at risk for complications including short bowel syndrome and neurodevelopmental disability.

Once a child is born prematurely, thought must be given to decreasing the risk for developing NEC. Toward that aim, the methods of providing hyperalimentation and oral feeds are both important. In a 2012 policy statement, the American Academy of Pediatrics recommended feeding preterm infants human milk, finding "significant short- and long-term beneficial effects," including reducing the rate of NEC by a factor of two or more.

A study by researchers in Peoria, IL, published in "Pediatrics" in 2008, demonstrated that using a higher rate of lipid (fats and/or oils) infusion for very low birth weight infants in the first week of life resulted in zero infants developing NEC in the experimental group, compared with 14% with NEC in the control group. (They started the experimental group at 2 g/kg/d of 20% IVFE and increased within two days to 3 g/kg/d; amino acids were started at 3 g/kg/d and increased to 3.5.)

Neonatologists at the University of Iowa reported on the importance of providing small amounts of trophic oral feeds of human milk starting as soon as possible, while the infant is being primarily fed intravenously, in order to prime the immature gut to mature and become ready to receive greater oral intake. Human milk from a milk bank or donor can be used if mother's milk is unavailable. The gut mucosal cells do not get enough nourishment from arterial blood supply to stay healthy, especially in very premature infants, where the blood supply is limited due to immature development of the capillaries, so nutrients from the lumen of the gut are needed.

A Cochrane review published in April 2014 has established that supplementation of probiotics enterally "prevents severe NEC as well as all-cause mortality in preterm infants."

Increasing amounts of milk by 30 to 40 ml/kg is safe in infant who are born weighing very little. Not beginning feeding an infant by mouth for more than 4 days does not appear to have protective benefits.

Data from the NICHD Neonatal Research Network's Glutamine Trial showed that the incidence of NEC among extremely low birthweight (ELBW, <1000 g) infants fed with more than 98% human milk from their mothers was 1.3%, compared with 11.1% among infants fed only preterm formula, and 8.2% among infants fed a mixed diet, suggesting that infant deaths could be reduced by efforts to support production of milk by mothers of ELBW newborns.

Research from the University of California, San Diego found that higher levels of one specific human milk oligosaccharide, disialyllacto-N-tetraose, may be protective against the development of NEC.

A study performed at Strong Memorial Hospital in Rochester, New York, showed that infants ≤ 60 days old meeting the following criteria were at low-risk for having a serious bacterial illness:

- generally well-appearing

- previously healthy

- full term (at ≥37 weeks gestation)

- no antibiotics perinatally

- no unexplained hyperbilirubinemia that required treatment

- no antibiotics since discharge

- no hospitalizations

- no chronic illness

- discharged at the same time or before the mother

- no evidence of skin, soft tissue, bone, joint, or ear infection

- White blood cells (WBCs) count 5,000-15,000/mm

- absolute band count ≤ 1,500/mm

- urine WBC count ≤ 10 per high power field (hpf)

- stool WBC count ≤ 5 per high power field (hpf) "only in infants with diarrhea"

Those meeting these criteria likely do not require a lumbar puncture, and are felt to be safe for discharge home without antibiotic treatment, or with a single dose of intramuscular antibiotics, but will still require close outpatient follow-up.

One risk for Group B streptococcal infection (GBS) is Preterm rupture of membranes. Screening women for GBS (via vaginal and rectal swabbing) and treating culture positive women with intrapartum chemoprophylaxis is reducing the number of neonatal sepsis caused by GBS.

PROM occurring before 37 weeks (PPROM) is one of the leading causes of preterm birth. 30-35% of all preterm births are caused by PPROM. This puts the fetus at risk for the many complications associated with prematurity such as respiratory distress, brain bleeds, infection, necrotizing enterocolitis (death of the fetal bowels), brain injury, muscle dysfunction, and death. Prematurity from any cause leads to 75% of perinatal mortality and about 50% of all long-term morbidity. PROM is responsible for 20% of all fetal deaths between 24 and 34 weeks gestation.

Inflammation can spread to other parts of the gut in patients with typhlitis. The condition can also cause the cecum to become distended and can cut off its blood supply. This and other factors can result in necrosis and perforation of the bowel, which can cause peritonitis and sepsis.

Historically, the mortality rate for typhlitis was as high as 50%, mostly because it is frequently associated with bowel perforation. More recent studies have demonstrated better outcomes with prompt medical management, generally with resolution of symptoms with neutrophil recovery without death

Specific types of enterocolitis include:

- necrotizing enterocolitis (most common in premature infants)

- pseudomembranous enterocolitis (also called "Pseudomembranous colitis")

Note that, in neonates, sepsis is difficult to diagnose clinically. They may be relatively asymptomatic until hemodynamic and respiratory collapse is imminent, so, if there is even a remote suspicion of sepsis, they are frequently treated with antibiotics empirically until cultures are sufficiently proven to be negative. In addition to fluid resuscitation and supportive care, a common antibiotic regimen in infants with suspected sepsis is a beta-lactam antibiotic (usually ampicillin) in combination with an aminoglycoside (usually gentamicin) or a third-generation cephalosporin (usually cefotaxime—ceftriaxone is generally avoided in neonates due to the theoretical risk of kernicterus.) The organisms which are targeted are species that predominate in the female genitourinary tract and to which neonates are especially vulnerable to, specifically Group B Streptococcus, "Escherichia coli", and "Listeria monocytogenes" (This is the main rationale for using ampicillin versus other beta-lactams.) Of course, neonates are also vulnerable to other common pathogens that can cause meningitis and bacteremia such as "Streptococcus pneumoniae" and "Neisseria meningitidis". Although uncommon, if anaerobic species are suspected (such as in cases where necrotizing enterocolitis or intestinal perforation is a concern, clindamycin is often added.

Granulocyte-macrophage colony stimulating factor (GM-CSF) is sometimes used in neonatal sepsis. However, a 2009 study found that GM-CSF corrects neutropenia if present but it has no effect on reducing sepsis or improving survival.

Trials of probiotics for prevention of neonatal sepsis have generally been too small and statistically underpowered to detect any benefit, but a randomized controlled trial that enrolled 4,556 neonates in India reported that probiotics significantly reduced the risk of developing sepsis. The probiotic used in the trial was "Lactobacillus plantarum".

A very large meta-analysis investigated the effect of probiotics on preventing late-onset sepsis (LOS) in neonates. Probiotics were found to reduce the risk of LOS, but only in babies who were fed human milk exclusively. It is difficult to distinguish if the prevention was a result of the probiotic supplementation or if it was a result of the properties of human milk. It is also still unclear if probiotic administration reduces LOS risk in extremely low birth weight infants due to the limited number of studies that investigated it. Out of the 37 studies included in this systematic review, none indicated any safety problems related to the probiotics. It would be beneficial to clarify the relationship between probiotic supplementation and human milk for future studies in order to prevent late onset sepsis in neonates.

In Germany, 90% of cases of infectious enteritis are caused by four pathogens, Norovirus, Rotavirus, "Campylobacter" and "Salmonella". Other common causes of infectious enteritis include bacteria such as "Shigella" and "E. coli," as well as viruses such as adenovirus, astrovirus and calicivirus. Other less common pathogens include "Bacillus cereus, Clostridium perfringens, Clostridium difficile" and "Staphylococcus aureus".

"Campylobacter jejuni" is one of the most common sources of infectious enteritis, and the most common bacterial pathogen found in 2 year old and smaller children with diarrhoea. It has been linked to consumption of contaminated water and food, most commonly poultry and milk. The disease tends to be less severe in developing countries, due to the constant exposure which people have with the antigen in the environment, leading to early development of antibodies.

Rotavirus is responsible for infecting 140 million people and causing 1 million deaths each year, mostly in children younger than 5 years. This makes it the most common cause of severe childhood diarrhoea and diarrhea-related deaths in the world. It selectively targets mature enterocytes in the small intestine, causing malabsorption, as well as inducing secretion of water. It has also been observed to cause villus ischemia, and increase intestinal motility. The net result of these changes is induced diarrhoea.

Enteritis necroticans is an often fatal illness, caused by β-toxin of "Clostridium perfringens". This causes inflammation and segments of necrosis throughout the gastrointestinal tract. It is most common in developing countries, however has also been documented in post-World War II Germany. Risk factors for enteritis necroticans include decreased trypsin activity, which prevent intestinal degradation of the toxin, and reduced intestinal motility, which increases likelihood of toxin accumulation.

Most cases of PROM occur spontaneously, but the risk of PROM in women undergoing a second trimester amniocentesis for prenatal diagnosis of genetic disorders is 1%. Although, no studies are known to account for all cases of PROM that stem from amniocentesis. This case, the chances of the membranes healing on their own and the amniotic fluid returning to normal levels is much higher than spontaneous PROM. Compared to spontaneous PROM, about 70% of women will have normal amniotic fluid levels within one month, and about 90% of babies will survive.

To date, the precise causative factor has not been verified, and the disease has been attributed by various sources to viruses, parasites, bacteria, use of antibiotics and sulfonamides, and heavy metal poisoning. Other possible causes include peracute salmonellosis, clostridial enterocolitis, and endotoxemia. "Clostridium difficile" toxins isolated in the horse have a genotype like the current human "epidemic strain", which is associated with human "C. difficile"-associated disease of greater than historical severity. "C. difficile" can cause pseudomembranous colitis in humans, and in hospitalized patients who develop it, fulminant "C. difficile" colitis is a significant and increasing cause of death.

Horses under stress appear to be more susceptible to developing colitis X. Disease onset is often closely associated with surgery or transport. Excess protein and lack of cellulose content in the diet (a diet heavy on grain and lacking adequate hay or similar roughage) is thought to be the trigger for the multiplication of clostridial organisms. A similar condition may be seen after administration of tetracycline or lincomycin to horses. These factors may be one reason the condition often develops in race horses, having been responsible for the deaths of the Thoroughbred filly Landaluce,

the Quarter Horse stallion Lightning Bar,

and is one theory for the sudden death of Kentucky Derby winner Swale.

The link to stress suggests the condition may be brought on by changes in the microflora of the cecum and colon that lower the number of anaerobic bacteria, increase the number of Gram-negative enteric bacteria, and decrease anaerobic fermentation of soluble carbohydrates, resulting in damage to the cecal and colonic mucosa and allowing increased absorption of endotoxins from the lumen of the gut.

The causative agent may be "Clostridium perfringens", type A, but the bacteria are recoverable only in the preliminary stages of the disease.

The suspect toxin could also be a form of "Clostridium difficile". In a 2009 study at the University of Arizona, "C. difficile" toxins A and B were detected, large numbers of "C. difficile" were isolated, and genetic characterization revealed them to be North American pulsed-field gel electrophoresis type 1, polymerase chain reaction ribotype 027, and toxinotype III. Genes for the binary toxin were present, and toxin negative-regulator tcdC contained an 18-bp deletion. The individual animal studied in this case was diagnosed as having peracute typhlocolitis, with lesions and history typical of those attributed to colitis X.

Use of antibiotics may also be associated with some forms of colitis-X. In humans, "C. difficile" is the most serious cause of antibiotic-associated diarrhea, often a result of eradication of the normal gut flora by antibiotics. In one equine study, colitis was induced after pretreatment with clindamycin and lincomycin, followed by intestinal content from horses which had died from naturally occurring idiopathic colitis. (A classic adverse effect of clindamycin in humans is "C. difficile"-associated diarrhea.) In the experiment, the treated horses died. After necropsy, "Clostridium cadaveris" was present, and is proposed as another possible causative agent in some cases of fatal colitis.

Crohn's disease – also known as regional enteritis, it can occur along any surface of the gastrointestinal tract. In 40% of cases it is limited to the small intestine.

Coeliac disease – caused by an autoimmune reaction to gluten by genetically predisposed individuals.

Eosinophilic enteropathy – a condition where eosinophils build up in the gastrointestinal tract and blood vessels, leading to polyp formation, necrosis, inflammation and ulcers. It is most commonly seen in patients with a history of atopy, however is overall relatively uncommon.

Enterocolitis or coloenteritis is an inflammation of the digestive tract, involving enteritis of the small intestine and colitis of the colon. It may be caused by various infections, with bacteria, viruses, fungi, parasites, or other causes. Common clinical manifestations of enterocolitis are frequent diarrheal defecations, with or without nausea, vomiting, abdominal pain, fever, chills, alteration of general condition. General manifestations are given by the dissemination of the infectious agent or its toxins throughout the body, or – most frequently – by significant losses of water and minerals, the consequence of diarrhea and vomiting.

Among the causal agents of acute enterocolitis are:

- bacteria: "Salmonella", "Shigella", "Escherichia coli", "Campylobacter" etc.;

- viruses: enteroviruses, rotaviruses, Norwalk virus, adenoviruses;

- fungi: candidiasis, especially in immunosuppressed patients or who have previously received prolonged antibiotic treatment;

- parasites: "Giardia lamblia" (with high frequency of infestation in the population, but not always with clinical manifestations), "Balantidium coli", "Blastocystis homnis", "Cryptosporidium" (diarrhea in people with immunosuppression), "Entamoeba histolytica" (produces the amebian dysentery, common in tropical areas).

The condition is usually caused by Gram-positive enteric commensal bacteria of the gut (gut flora). "Clostridium difficile" is a species of Gram-positive bacteria that commonly causes severe diarrhea and other intestinal diseases when competing bacteria are wiped out by antibiotics, causing pseudomembranous colitis, whereas Clostridium septicum is responsible for most cases of neutropenic enterocolitis.

Typhlitis most commonly occurs in immunocompromised patients, such as those undergoing chemotherapy, patients with AIDS, kidney transplant patients, or the elderly.

There is no cure for short bowel syndrome except transplant. In newborn infants, the 4-year survival rate on parenteral nutrition is approximately 70%. In newborn infants with less than 10% of expected intestinal length, 5 year survival is approximately 20%. Some studies suggest that much of the mortality is due to a complication of the total parenteral nutrition (TPN), especially chronic liver disease. Much hope is vested in Omegaven, a type of lipid TPN feed, in which recent case reports suggest the risk of liver disease is much lower.

Although promising, small intestine transplant has a mixed success rate, with postoperative mortality rate of up to 30%. One-year and 4-year survival rate are 90% and 60%, respectively.

Early onset sepsis can occur in the first week of life. It usually is apparent on the first day after birth. This type of infection is usually acquired before the birth of the infant. Premature rupture of membranes and other obstetrical complications can add to the risk of early-onset sepsis. If the amniotic membrane has been ruptured greater than 18 hours before delivery the infant may be at more risk for this complication. Prematurity, low birth weight, chorioamnionitis, maternal urinary tract infection and/or maternal fever are complications that increase the risk for early-onset sepsis. Early onset sepsis is indicated by serious respiratory symptoms. The infant usually suffers from pneumonia, hypothermia, or shock. The mortality rate is 30 to 50%.

In adults, most common causes are hemorrhoids and diverticulosis, both of which are relatively benign; however, it can also be caused by colorectal cancer, which is potentially fatal. In a newborn infant, haematochezia may be the result of swallowed maternal blood at the time of delivery, but can also be an initial symptom of necrotizing enterocolitis, a serious condition affecting premature infants. In babies, haematochezia in conjunction with abdominal pain is associated with intussusception. In adolescents and young adults, inflammatory bowel disease, particularly ulcerative colitis, is a serious cause of haematochezia that must be considered and excluded.

Hematochezia can be due to upper gastrointestinal bleeding. However, as the blood from such a bleed is usually chemically modified by action of acid and enzymes, it presents more commonly as black "tarry" feces known as melena. Haematochezia from an upper gastrointestinal source is an ominous sign, as it suggests a very significant bleed which is more likely to be life-threatening.

Beeturia can cause red colored feces after eating beets because of insufficient metabolism of a red pigment, and is a differential sign that may be mistaken as hematochezia.

Consumption of dragon fruit or pitaya may also cause red discoloration of the stool and sometimes the urine (pseudohematuria). This too, is a differential sign that is sometimes mistaken for hematochezia.

In infants, the Apt test can be used to distinguish fetal hemoglobin from maternal blood.

Other common causes of blood in the stool include:

- Colorectal cancer

- Crohns disease

- Ulcerative colitis

- Other types of inflammatory bowel disease, inflammatory bowel syndrome, or ulceration

- Rectal or anal hemorrhoids or anal fissures, particularly if they rupture or are otherwise irritated

- "Shigella" or shiga toxin producing "E. coli" food poisoning

- Necrotizing enterocolitis

- Diverticulosis

- Salmonellosis

- Upper gastrointestinal bleeding

- Peptic ulcer disease

- Esophageal varices

- Gastric cancer

- Intense exercise, especially a high-impact activity like running in hot weather.

Infections that occur after the first week of life but before the age of 30 days are considered late onset infections. Obstetrical and maternal complications are not typically the cause of these late onset infections; they are usually acquired by the infant in the hospital neonatal intensive care unit. The widespread use of broad-spectrum antibiotics in the nursery intensive care unit can cause a higher prevalence of invasive antibiotic resistant bacteria. Meconium aspiration syndrome has a mortality rate just over 4%. This accounts for 2% for all neonatal deaths.

A number of factors have been identified that are linked to a higher risk of a preterm birth such as being less than 18 years of age. Maternal height and weight can play a role.

Further, in the US and the UK, black women have preterm birth rates of 15–18%, more than double than that of the white population. Filipinos are also at high risk of premature birth, and it is believed that nearly 11-15% of Filipinos born in the U.S. (compared to other Asians at 7.6% and whites at 7.8%) are premature. Filipinos being a big risk factor is evidenced with the Philippines being the 8th highest ranking in the world for preterm births, the only non-African country in the top 10. This discrepancy is not seen in comparison to other Asian groups or Hispanic immigrants and remains unexplained.

Pregnancy interval makes a difference as women with a six-month span or less between pregnancies have a two-fold increase in preterm birth. Studies on type of work and physical activity have given conflicting results, but it is opined that stressful conditions, hard labor, and long hours are probably linked to preterm birth.

A history of spontaneous (i.e., miscarriage) or surgical abortion has been associated with a small increase in the risk of preterm birth, with an increased risk with increased number of abortions, although it is unclear whether the increase is caused by the abortion or by confounding risk factors (e.g., socioeconomic status). Increased risk has not been shown in women who terminated their pregnancies medically. Pregnancies that are unwanted or unintended are also a risk factor for preterm birth.

Adequate maternal nutrition is important. Women with a low BMI are at increased risk for preterm birth. Further, women with poor nutrition status may also be deficient in vitamins and minerals. Adequate nutrition is critical for fetal development and a diet low in saturated fat and cholesterol may help reduce the risk of a preterm delivery. Obesity does not directly lead to preterm birth; however, it is associated with diabetes and hypertension which are risk factors by themselves. To some degree those individuals may have underlying conditions (i.e., uterine malformation, hypertension, diabetes) that persist.

Women with celiac disease have an increased risk of the development of preterm birth. The risk of preterm birth is more elevated when celiac disease remains undiagnosed and untreated.

Marital status is associated with risk for preterm birth. A study of 25,373 pregnancies in Finland revealed that unmarried mothers had more preterm deliveries than married mothers (P=0.001). Pregnancy outside of marriage was associated overall with a 20% increase in total adverse outcomes, even at a time when Finland provided free maternity care. A study in Quebec of 720,586 births from 1990 to 1997 revealed less risk of preterm birth for infants with legally married mothers compared with those with common-law wed or unwed parents.

Genetic make-up is a factor in the causality of preterm birth. Genetics has been a big factor into why Filipinos have a high risk of premature birth as the Filipinos have a large prevalence of mutations that help them be predisposed to premature births. An intra- and transgenerational increase in the risk of preterm delivery has been demonstrated. No single gene has been identified.

Subfertility is associated with preterm birth. Couples who have tried more than 1 year versus those who have tried less than 1 year before achieving a spontaneous conception have an adjusted odds ratio of 1.35 (95% confidence interval 1.22-1.50) of preterm birth. Pregnancies after IVF confers a greater risk of preterm birth than spontaneous conceptions after more than 1 year of trying, with an adjusted odds ratio of 1.55 (95% CI 1.30-1.85).

Short bowel syndrome in adults and children is usually caused by surgery. This surgery may be done for:

- Crohn's disease, an inflammatory disorder of the digestive tract

- Volvulus, a spontaneous twisting of the small intestine that cuts off the blood supply and leads to tissue death

- Tumors of the small intestine

- Injury or trauma to the small intestine

- Necrotizing enterocolitis (premature newborn)

- Bypass surgery to treat obesity

- Surgery to remove diseases or damaged portion of the small intestine

Some children are also born with an abnormally short small intestine, known as congenital short bowel.

Pneumatosis intestinalis (also called intestinal pneumatosis, pneumatosis cystoides intestinalis, or pneumatosis coli) is of an intestine, that is, gas cysts in the bowel wall. As a radiological sign it is highly suggestive for necrotizing enterocolitis. This is in contrast to gas in the intestinal lumen (which is relieved by flatulence). In newborns, pneumatosis intestinalis is considered diagnostic for necrotizing enterocolitis, and the air is produced by bacteria in the bowel wall. The pathogenesis of pneumatosis intestinalis is poorly understood and is likely multifactorial. PI itself is not a disease, but rather a clinical sign. In some cases, PI is an incidental finding, whereas in others, it portends a life-threatening intra-abdominal condition.

Treatment for colitis-X usually does not save the horse. The prognosis is average to poor, and mortality is 90% to 100%. However, treatments are available, and one famous horse that survived colitis-X was U.S. Triple Crown winner Seattle Slew, that survived colitis-X in 1978 and went on to race as a four-year-old.

Large amounts of intravenous fluids are needed to counter the severe dehydration, and electrolyte replacement is often necessary. Flunixin meglumine (Banamine) may help block the effects of toxemia. Mortality rate has been theorized to fall to 75% if treatment is prompt and aggressive, including administration of not only fluids and electrolytes, but also blood plasma, anti-inflammatory and analgesic drugs, and antibiotics. Preventing dehydration is extremely important. Nutrition is also important. Either parenteral or normal feeding can be used to support the stressed metabolism of the sick horse. Finally, the use of probiotics is considered beneficial in the restoration of the normal intestinal flora. The probiotics most often used for this purpose contain "Lactobacillus" and "Bifidobacterium".

The use of fertility medication that stimulates the ovary to release multiple eggs and of IVF with embryo transfer of multiple embryos has been implicated as an important factor in preterm birth. Maternal medical conditions increase the risk of preterm birth. Often labor has to be induced for medical reasons; such conditions include high blood pressure, pre-eclampsia, maternal diabetes, asthma, thyroid disease, and heart disease.

In a number of women anatomical issues prevent the baby from being carried to term. Some women have a weak or short cervix (the strongest predictor of premature birth) Women with vaginal bleeding during pregnancy are at higher risk for preterm birth. While bleeding in the third trimester may be a sign of placenta previa or placental abruption – conditions that occur frequently preterm – even earlier bleeding that is not caused by these conditions is linked to a higher preterm birth rate. Women with abnormal amounts of amniotic fluid, whether too much (polyhydramnios) or too little (oligohydramnios), are also at risk.

The mental status of the women is of significance. Anxiety and depression have been linked to preterm birth.

Finally, the use of tobacco, cocaine, and excessive alcohol during pregnancy increases the chance of preterm delivery. Tobacco is the most commonly abused drug during pregnancy and contributes significantly to low birth weight delivery. Babies with birth defects are at higher risk of being born preterm.

Passive smoking and/or smoking before the pregnancy influences the probability of a preterm birth. The World Health Organization published an international study in March 2014.

Presence of anti-thyroid antibodies is associated with an increased risk preterm birth with an odds ratio of 1.9 and 95% confidence interval of 1.1–3.5.

A 2004 systematic review of 30 studies on the association between intimate partner violence and birth outcomes concluded that preterm birth and other adverse outcomes, including death, are higher among abused pregnant women than among non-abused women.

The Nigerian cultural method of abdominal massage has been shown to result in 19% preterm birth among women in Nigeria, plus many other adverse outcomes for the mother and baby. This ought not be confused with massage conducted by a fully trained and licensed massage therapist or by significant others trained to provide massage during pregnancy, which has been shown to have numerous positive results during pregnancy, including the reduction of preterm birth, less depression, lower cortisol, and reduced anxiety.

Oesophageal diseases include a spectrum of disorders affecting the oesophagus. The most common condition of the oesophagus in Western countries is gastroesophageal reflux disease, which in chronic forms is thought to result in changes to the epithelium of the oesophagus, known as Barrett's oesophagus.

Acute disease might include infections such as oesophagitis, trauma caused ingestion of corrosive substances, or rupture of veins such as oesophageal varices, Boerhaave syndrome or Mallory-Weiss tears. Chronic diseases might include congenital diseases such as Zenker's diverticulum and esophageal webbing, and oesophageal motility disorders including the nutcracker oesophagus, achalasia, diffuse oesophageal spasm, and oesophageal stricture.

Oesophageal disease may result in a sore throat, throwing up blood, difficulty swallowing or vomiting. Chronic or congenital diseases might be investigated using barium swallows, endoscopy and biopsy, whereas acute diseases such as reflux may be investigated and diagnosed based on symptoms and a medical history alone.

CNE is a necrotizing inflammation of the small bowel (especially the jejunum but also the ileum). Clinical results may vary from mild diarrhea to a life-threatening sequence of severe abdominal pain, vomiting, bloody stool, ulceration of the small intestine with leakage (perforation) into the peritoneal cavity and possible death within a single day due to peritonitis. Many patients exhibit meteorism. Treatment involves suppressing the toxin-producing organisms with antibiotics such as penicillin G or metronidazole. About half of seriously ill patients require surgery for perforation, persistent intestinal obstruction, or failure to respond to the antibiotics. An investigational toxoid vaccine has been used successfully in some developing countries but is not available outside of research.

Diseases of the hepatobiliary system affect the biliary tract (also known as the "biliary tree"), which secretes bile in order to aid digestion of fats. Diseases of the gallbladder and bile ducts are commonly diet-related, and may include the formation of gallstones that impact in the gallbladder (cholecystolithiasis) or in the common bile duct (choledocholithiasis).

Gallstones are a common cause of inflammation of the gallbladder, called cholecystitis. Inflammation of the biliary duct is called cholangitis, which may be associated with autoimmune disease, such as primary sclerosing cholangitis, or a result of bacterial infection, such as ascending cholangitis.

Disease of the biliary tree may cause pain in the upper right abdomen, particularly when pressed. Disease might be investigated using ultrasound or ERCP, and might be treated with drugs such as antibiotics or UDCA, or by the surgical removal of the gallbladder.