Endotoxemia is a serious complication of colic and warrants aggressive treatment. Endotoxin (lipopolysaccharide) is released from the cell wall of gram-negative bacteria when they die. Normally, endotoxin is prevented from entering systemic circulation by the barrier function of the intestinal mucosa, antibodies and enzymes which bind and neutralize it and, for the small amount that manages to enter the blood stream, removal by Kupffer cells in the liver. Endotoxemia occurs when there is an overgrowth and secondary die-off of gram negative bacteria, releasing mass quantities of endotoxin. This is especially common when the mucosal barrier is damaged, as with ischemia of the GI tract secondary to a strangulating lesion or displacement. Endotoxemia produces systemic effects such as cardiovascular shock, insulin resistance, and coagulation abnormalities.

Fluid support is essential to maintain blood pressure, often with the help of colloids or hypertonic saline. NSAIDs are commonly given to reduce systemic inflammation. However, they decrease the levels of certain prostaglandins that normally promote healing of the intestinal mucosa, which subsequently increases the amount of endotoxin absorbed. To counteract this, NSAIDs are sometimes administered with a lidocaine drip, which appears to reduce this particular negative effect. Flunixin may be used for this purpose at a dose lower than that used for analgesia, so can be safely given to a colicky horse without risking masking signs that the horse requires surgery. Other drugs that bind endotoxin, such as polymyxin B and Bio-Sponge, are also often used. Polymixin B prevents endotoxin from binding to inflammatory cells, but is potentially nephrotoxic, so should be used with caution in horses with azotemia, especially neonatal foals. Plasma may also be given with the intent of neutralizing endotoxin.

Laminitis is a major concern in horses suffering from endotoxemia. Ideally, prophylactic treatment should be provided to endotoxic horses, which includes the use of NSAIDs, DMSO, icing of the feet, and frog support. Horses are also sometimes administered heparin, which is thought to reduce the risk of laminitis by decreasing blood coagulability and thus blood clot formation in the capillaries of the foot.

Horses are withheld feed when colic signs are referable to gastrointestinal disease. In long-standing cases, parenteral nutrition may be instituted. Once clinical signs improve, the horse will slowly be re-fed (introduced back to its normal diet), while being carefully monitored for pain.

Surgical intervention is nearly always required in form of exploratory laparotomy and closure of perforation with peritoneal wash. Occasionally they may be managed laparoscopically.

Conservative treatment including intravenous fluids, antibiotics, nasogastric aspiration and bowel rest is indicated only if the person is nontoxic and clinically stable.

Recurrence of gastric dilatation-volvulus attacks can be a problem, occurring in up to 80 percent of dogs treated medically only (without surgery). To prevent recurrence, at the same time the bloat is treated surgically, a right-side gastropexy is often performed, which by a variety of methods firmly attaches the stomach wall to the body wall, to prevent it from twisting inside the abdominal cavity in the future. While dogs that have had gastropexies still may develop gas distension of the stomach, there is a significant reduction in recurrence of gastric volvulus. One study showed that out of 136 dogs that had surgery for gastric dilatation-volvulus, 4.3 percent of those that did have gastropexies had a recurrence, while 54.5 percent of those without the additional surgery recurred. Gastropexies are also performed prophylactically in dogs considered to be at high risk of gastric dilatation-volvulus, including dogs with previous episodes of gastric dilatation-volvulus or with gastrointestinal disease predisposing to gastric dilatation-volvulus, and dogs with a first-order relative (parent or sibling) with a history of gastric dilatation-volvulus.

Precautions that are likely to help prevent gastric dilatation-volvulus include feeding small meals throughout the day instead of one big meal and not exercising immediately before or after a meal.

Treatment of gastric outlet obstruction depends on the cause, but is usually either surgical or medical.

In most people with peptic ulcer disease, the oedema will usually settle with conservative management with nasogastric suction, replacement of fluids and electrolytes and proton pump inhibitors.

Immediate treatment is the most important factor in a favorable prognosis. A delay in treatment greater than six hours or the presence of peritonitis, sepsis, hypotension, or disseminated intravascular coagulation are negative prognostic indicators.

Historically, GDV has held a guarded prognosis. Although "early studies showed mortality rates between 33% and 68% for dogs with GDV," studies from 2007 to 2012 "reported mortality rates between 10% and 26.8%". Mortality rates approach 10% to 40% even with treatment. A study determined that with prompt treatment and good preoperative stabilization of the patient, mortality is significantly lessened to 10% overall (in a referral setting). Negative prognostic indicators following surgical intervention include postoperative cardiac arrhythmia, splenectomy, or splenectomy with partial gastric resection. Interestingly, a longer time from presentation to surgery was associated with a lower mortality, presumably because these dogs had received more complete preoperative fluid resuscitation and were thus better cardiovascularly stabilized prior to the procedure.

Gastrointestinal perforation, also known as ruptured bowel, is a hole in the wall of part of the gastrointestinal tract. The gastrointestinal tract includes the esophagus, stomach, small intestine, and large intestine. Symptoms include severe abdominal pain and tenderness. When the hole is in the stomach or early part of the small intestine the onset of pain is typically sudden while with a hole in the large intestine onset may be more gradual. The pain is usually constant in nature. Sepsis, with an increased heart rate, increased breathing rate, fever, and confusion may occur.

The cause can include trauma such as from a knife wound, eating a sharp object, or a medical procedure such as colonoscopy, bowel obstruction such as from a volvulus, colon cancer, or diverticulitis, stomach ulcers, ischemic bowel, and a number of infections including "C. difficile". A hole allows intestinal contents to enter the abdominal cavity. The entry of bacteria results in a condition known as peritonitis or in the formation of an abscess. A hole in the stomach can also lead to a chemical peritonitis due to gastric acid. A CT scan is typically the preferred method of diagnosis; however, free air from a perforation can often be seen on plain X-ray.

Perforation anywhere along the gastrointestinal tract typically requires emergency surgery in the form of an exploratory laparotomy. This is usually carried out along with intravenous fluids and antibiotics. A number of different antibiotics may be used such as piperacillin/tazobactam or the combination of ciprofloxacin and metronidazole. Occasionally the hole can be sewn closed while other times a bowel resection is required. Even with maximum treatment the risk of death can be as high as 50%. A hole from a stomach ulcer occurs in about 1 per 10,000 people per year, while one from diverticulitis occurs in about 0.4 per 10,000 people per year.

Proximal enteritis usually is managed medically. This includes nasogastric intubation every 1–2 hours to relieve gastric pressure secondary to reflux, which often produces to 2–10 L, as well as aggressive fluid support to maintain hydration and correct electrolyte imbalances. Maintaining hydration in these patients can be very challenging. In some cases, fluid support may actually increase reflux production, due to the decreased intravascular oncotic pressure from low total protein and albumin levels, leading to loss of much of these IV fluids into the intestinal lumen. These horses will often display dependent edema (edema that collects in locations based on gravity). Colloids such as plasma or Hetastarch may be needed to improve intravascular oncotic pressure, although they can be cost prohibitive for many owners. Reflux levels are monitored closely to help evaluate fluid losses, and horses recovering from DPJ show improved hydration with decreased reflux production and improved attitude.

Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used for pain relief, reduction of inflammation, and for their anti-endotoxin effects, but care must be taken since they may produce gastrointestinal ulceration and damage the kidneys. Due to a suspected link to "Clostridial" infection, anti-microbials are often administered, usually penicillin or metronidazole. Aminoglycosides should be used with extreme caution due to the risk of nephrotoxicosis (damage to the kidney). The mucosa of the intestines is damaged with DPJ, often resulting in absorption of endotoxin and risking laminitis, so therapy to combat and treat endotoxemia is often employed. This includes treatment with drugs that counteract endotoxin such as Polymyxin B and Bio-Sponge, fluid support, and laminitis prevention such as icing of the feet. Prokinetic drugs such as lidocaine, erythromycin, metoclopramide, and bethanechol are often used to treat the ileus associated with the disease.

Horses are withheld food until reflux returns to less than 1–2 L of production every 4 hours, and gut sounds return, often requiring 3–7 days of therapy. Parenteral nutrition is often provided to horses that are withheld feed for greater than 3–4 days. It is suspected to improve healing and shorten the duration of the illness, since horses often become cachexic due to the protein losing enteropathy associated with this disease.

Surgery may need to be performed to rule out colic with similar presenting signs such as obstruction or strangulation, and in cases that are long-standing (> 7 days) to perform a resection and anastomosis of the diseased bowel. However, some horses have recovered with long-term medical support (up to 20 days).

Diagnostic measures can be used as interventions to help stop bleeding in some cases. Bleeding that occurs due to a neoplasm (cancer growth) can be treated using colonoscopy and clipping, surgical intervention, or other measures, depending on the form and stage of cancer. Similarly, gastric cancer is treated depending on the staging, although typically requires surgical and medical therapy.

The treatment for motility issues, namely constipation, is typically to improve the movement of waste though the GI tract. This is done by using stool softeners (which work by pulling water into the stool while in the colon), addition of fiber to the diet, and use of osmotic laxatives (which help fluid movement through the colon, improving overall motility). Improving a persons gut motility can reduce the straining during defection and decrease the risk of developing of anal fissures. Anal fissures are associated with pain and blood on the toilet paper, and require time for healing. Treatment includes topical nitrates or calcium channel blockers and surgical interventions for chronic or complex cases. Similar to anal fissures, internal hemorrhoids can cause blood on the tissue when wiping, and be felt at the opening of the anus. Treatment options for hemorrhoids can be dependent on whether an underlying cause exists. An anorectal varices related hemorrhoids caused by cirrhosis, however symptomatic treatment often involves removal.

Colitis can be divided into infectious and drug induced, as can the treatment for these conditions. With infectious colitis, treatment is pathogen dependent, and generally requires the use of antibiotics. With drug-induced colitis, treatment typically involves removal of the offending agent, as is the case in NSAID induced PUD, however, removing radiation from a cancer patient is not always practical within a treatment regimen, so medical treatment is the primary mode of treatment.

Structural compromise leading to blood in stool is caused by a variety of conditions, and therefore requires different treatment for each condition. Peptic ulcer disease alone can be divided into multiple causes, but is generally initially controlled primarily with a proton pump inhibitor, with the addition of an H blocker, or in serious cases, requiring surgical intervention. Diverticulitis and diverticulosis require antibiotic treatment, and may require surgical intervention.

Inflammatory bowel disease is also divided into separate conditions, namely ulcerative colitis and Crohn's disease, which have different medical treatment regimens, and may require surgical intervention in more serious conditions.

Horses may develop pharyngitis, laryngitis, or esophagitis secondary to indwelling nasogastric tube. Other complications include thrombophlebitis, laminitis (which subsequently reduces survival rate), and weight loss. Horses are also at increased risk of hepatic injury.

Survival rates for DPJ are 25–94%. Horses that survive the incident rarely have reoccurrence.

Treatment is surgical, potentially with a laparoscopic resection. In patients with bleeding, strangulation of bowel, bowel perforation or bowel obstruction, treatment involves surgical resection of both the Meckel's diverticulum itself along with the adjacent bowel segment, and this procedure is called a "small bowel resection". In patients without any of the aforementioned complications, treatment involves surgical resection of the Meckel's diverticulum only, and this procedure is called a simple diverticulectomy.

With regards to asymptomatic Meckel's diverticulum, some recommend that a search for Meckel's diverticulum should be conducted in every case of appendectomy/laparotomy done for acute abdomen, and if found, Meckel's diverticulectomy or resection should be performed to avoid secondary complications arising from it.

Smoking has been linked to a variety of disorders of the stomach. Tobacco is known to stimulate acid production and impairs production of the protective mucus. This leads to development of ulcers in the majority of smokers.

Chronic stomach problems have also been linked to excess intake of alcohol. It has been shown that alcohol intake can cause stomach ulcer, gastritis and even stomach cancer. Thus, avoidance of smoking and excess alcohol consumption can help prevent the majority of chronic stomach disorders.

One of the most causes of chronic stomach problems is use of medications. Use of aspirin and other non-steroidal anti-inflammatory drugs to treat various pain disorders can damage lining of the stomach and cause ulcers. Other medications like narcotics can interfere with stomach emptying and cause bloating, nausea, or vomiting.

The majority of chronic stomach problems are treated medically. However, there is evidence that a change in life style may help. Even though there is no specific food responsible for causing chronic stomach problems, experts recommend eating a healthy diet which consists of fruits and vegetables. Lean meat should be limited. Moreover, people should keep a diary of foods that cause problems and avoid them.

Organ perforation is a complete penetration of the wall of a hollow organ in the body, such as the gastrointestinal tract in the case of gastrointestinal perforation. It mainly refers to accidental or pathologic perforation, rather than intentional penetration during surgery.

Types include gastrointestinal perforation and uterine perforation.

With the exception of a few case reports describing survival without surgery, the mortality of untreated Boerhaave syndrome is nearly 100%. Its treatment includes immediate antibiotic therapy to prevent mediastinitis and sepsis, surgical repair of the perforation, and if there is significant fluid loss it should be replaced with IV fluid therapy since oral rehydration is not possible. Even with early surgical intervention (within 24 hours) the risk of death is 25%.

Distal or sigmoid, fecalomas can often be disimpacted digitally or by a catheter which carries a flow of disimpaction fluid (water or other solvent or lubricant). Surgical intervention in the form of sigmoid colectomy or proctocolectomy and ileostomy may be required only when all conservative measures of evacuation fail.

A perforated ulcer, is a condition in which untreated ulcer can burn through the wall of the stomach (or other areas of the gastrointestinal tract), allowing digestive juices and food to leak into the abdominal cavity. Treatment generally requires immediate surgery. The ulcer is known initially as a peptic ulcer before the ulcer burns through the full thickness of the stomach or duodenal wall. A diagnosis is made by taking an erect abdominal/chest X-ray (seeking air under the diaphragm). This is in fact one of the very few occasions in modern times where surgery is undertaken to treat an ulcer. Many perforated ulcers have been attributed to the bacterium "Helicobacter pylori". The incidence of perforated ulcer is steadily declining, though there are still incidents where it occurs. Causes include smoking and nonsteroidal anti-inflammatory drugs (NSAIDs). A perforated ulcer can be grouped into a stercoral perforation which involves a number of different things that causes perforation of the intestine wall. The first symptom of a perforated peptic ulcer is usually sudden, severe, sharp pain in the abdomen. The experience is typically so intense that most people precisely recall the exact moment the pain began. The pain is typically at its maximum immediately and persists. It is characteristically made worse by any movement, and greatly intensifies with coughing or sneezing.

Meckel's diverticulum occurs in about 2% of the population. Prevalence in males is 3–5 times higher than in females. Only 2% of cases are symptomatic, which usually presents among children at the age of 2.

Most cases of Meckel's diverticulum are diagnosed when complications manifest or incidentally in unrelated conditions such as laparotomy, laparoscopy or contrast study of the small intestine. Classic presentation in adults includes intestinal obstruction and inflammation of the diverticulum (diverticulitis). Painless rectal bleeding most commonly occurs in toddlers.

Inflammation in the ileal diverticulum has symptoms that mimic appendicitis, therefore its diagnosis is of clinical importance. Detailed knowledge of the pathophysiological properties is essential in dealing with the life-threatening complications of Meckel's diverticulum.

The treatment for bile reflux is the same as the treatment for acidic reflux. In general, everything that can

reduce acidic reflux can reduce bile reflux. Examples include lifestyle modification, weight reduction, and the avoidance of eating immediately before sleep or being in the supine position immediately after meals. In addition, smoking has been found to be a factor in the development of acidic reflux. Thus, all of these factors should be applied to bile reflux as well.

Likewise, drugs that reduce the secretion of gastric acid (e.g., proton pump inhibitors)

or that reduce gastric contents or volume can be used to treat acidic bile reflux. Because prokinetic drugs increase the motility of the stomach and accelerate gastric emptying, they can also reduce bile reflux. Other drugs that reduce the relaxations of the lower esophageal sphincter, such as baclofen, have also proven to reduce bile reflux, particularly in patients who are refractory to (medically unresponsive to) proton pump inhibitor therapy.

Medications used in managing biliary reflux include bile acid sequestrants, particularly cholestyramine, which disrupt the circulation of bile in the digestive tract and sequester bile that would otherwise cause symptoms when refluxed; and prokinetic agents, to move material from the stomach to the small bowel more rapidly and prevent reflux.

Biliary reflux may also be treated surgically, if medications are ineffective or if precancerous tissue is present in the esophagus.

Gastric volvulus of unknown cause comprises two thirds of cases and is presumably due to abnormal laxity of the gastrosplenic, gastroduodenal, gastrophrenic, and gastrohepatic ligaments. Type 1 gastric volvulus is more common in adults but has been reported in children.

Gastric volvulus or volvulus of stomach is a twisting of all or part of the stomach by more than 180 degrees with obstruction of the flow of material through the stomach, variable loss of blood supply and possible tissue death. The twisting can occur around the long axis of the stomach: this is called organoaxial or around the axis perpendicular to this, called mesenteroaxial. Obstruction is more likely in organoaxial twisting than with mesenteroaxial while the latter is more associated with ischemia. About one third of the cases are associated with a hiatus hernia. Treatment is surgical.

The classic triad (Borchardt's Triad) of gastric volvulus, described by Borchardt in 1904, consists of severe epigastric pain, retching (due to sour taste in mouth) without vomiting, inability to pass a nasogastric tube and reportedly occurs in 70% of cases. Sometimes severe pain at the top of left shoulder, this may be due to internal bleeding irritating the diaphragm upon respiration.

Anemia is a common complication of blood in the stool, especially when there is a large amount of blood or bleeding occurs over a long period of time. Anemia is also commonly associated with an iron deficiency, due to the importance of iron in the formation of red blood cells (RBCs). When anemia is diagnosed as a result of blood in the stool, vitamins that are important for RBC formation (folate, vitamin B12, and vitamin C) are frequently prescribed in order to ensure that all the materials are available for those cells that are made.

Perforated peptic ulcer is a surgical emergency and requires surgical repair of the perforation. Most bleeding ulcers require endoscopy urgently to stop bleeding with cautery, injection, or clipping.

H2 antagonists or proton-pump inhibitors decrease the amount of acid in the stomach, helping with healing of ulcers.

The role of "Helicobacter pylori" in functional dyspepsia is controversial, and no clear causal relationship has been established. This is true for both the symptom profile and pathophysiology of functional dyspepsia. Although some epidemiologic studies have suggested an association between "H. pylori" infection and functional dyspepsia, others have not. The discrepancy may stem in part from differences in methodology and lack of adequate consideration of confounding factors such as past history of peptic ulcer disease and socioeconomic status. Controlled trials disagree about whether or not "H. pylori" eradication is beneficial in functional dyspepsia, with roughly half of the trials showing improvement and the other half no improvement. In a recent multicenter U.S. trial that randomized 240 patients to treatment or placebo, and followed patients for 12 months, 28% of treated patients versus 23% of those receiving placebo reported relief of symptoms at the 12-month follow-up. Similarly, recent European trials have not shown significant differences in symptoms after "H. pylori" eradication as compared with controls. Systematic reviews of eradication have been conducted, with varying results. A systematic review in the Annals of Internal Medicine suggested no statistically significant effect, with an odds ratio (OR) for treatment success versus control of 1.29 (95% CI, 0.89–1.89; P = 0.18). Still, no effect was seen after adjusting for heterogeneity and for cure of "H. pylori". In contrast, a Cochrane review found a small but statistically significant effect in curing symptoms ("H. pylori" cure vs placebo, 36% vs 30%, respectively).