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).

Acute, self-limited "dyspepsia" may be caused by overeating, eating too quickly, eating high-fat foods, eating during stressful situations, or drinking too much alcohol or coffee. Many medications cause dyspepsia, including aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics (metronidazole, macrolides), diabetes drugs (metformin, Alpha-glucosidase inhibitor, amylin analogs, GLP-1 receptor antagonists), antihypertensive medications (angiotensin converting enzyme [ACE] inhibitors, Angiotensin II receptor antagonist), cholesterol-lowering agents (niacin, fibrates), neuropsychiatric medications (cholinesterase inhibitors [donepezil, rivastigmine]), SSRIs (fluoxetine, sertraline), serotonin-norepinephrine-reuptake inhibitors (venlafaxine, duloxetine), Parkinson drugs (Dopamine agonist, monoamine oxidase [MAO]-B inhibitors), corticosteroids, estrogens, digoxin, iron, and opioids.

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.

Cancers of the stomach are rare and the incidence has been declining worldwide. Stomach cancers usually occur due to fluctuations in acidity level and may present with vague symptoms of abdominal fullness, weight loss and pain. The actual cause of stomach cancer is not known but has been linked to infection with "Helicobacter pylori", pernicious anemia, Menetriere's disease, and nitrogenous preservatives in food.

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.

Gastric diseases refer to diseases affecting the stomach. Inflammation of the stomach by infection from any cause is called gastritis, and when including other parts of the gastrointestinal tract called gastroenteritis. When gastritis persists in a chronic state, it is associated with several diseases, including atrophic gastritis, pyloric stenosis, and gastric cancer. Another common condition is gastric ulceration, peptic ulcers. Ulceration erodes the gastric mucosa, which protects the tissue of the stomach from the stomach acids. Peptic ulcers are most commonly caused by a bacterial "Helicobacter pylori" infection.

As well as peptic ulcers, vomiting blood may result from abnormal arteries or veins that have ruptured, including Dieulafoy's lesion and Gastric antral vascular ectasia. Congenital disorders of the stomach include pernicious anaemia, in which a targeted immune response against parietal cells results in an inability to absorb vitamin B12. Other common symptoms that stomach disease might cause include indigestion or dyspepsia, vomiting, and in chronic disease, digestive problems leading to forms of malnutrition. In addition to routine tests, an endoscopy might be used to examine or take a biopsy from the stomach.

There is considerable research into the causes, diagnosis and treatments for FGIDs. Diet, microbiome, genetics, neuromuscular function and immunological response all interact. Heightened mast cell activation has been proposed to be a common factor among FGIDs, contributing to visceral hypersensitivity as well as epithelial, neuromuscular, and motility dysfunction.

Functional gastrointestinal disorders (FGID) include a number of separate idiopathic disorders which affect different parts of the gastrointestinal tract and involve visceral hypersensitivity and impaired gastrointestinal motility.

Some individuals may benefit from diet modification, such as a reduced fat diet, following cholecystectomy. The liver produces bile and the gallbladder acts as reservoir. From the gallbladder, bile enters the intestine in individual portions. In the absence of gallbladder, bile enters the intestine constantly, but in small quantities. Thus, it may be insufficient for digestion of fatty foods. Postcholecystectomy syndrome treatment depends on the identified violations that led to it. Typically, the patient is recommended dietary restriction table with fatty foods, enzyme preparations, antispasmodics, sometimes cholagogue.

If the pain is caused by biliary microlithiasis, oral ursodeoxycholic acid can alleviate the condition.

A trial of bile acid sequestrant therapy is recommended for bile acid diarrhoea.

A Low FODMAP diet now has an evidence base sufficiently strong to recommend its widespread application in conditions such as IBS and IBD. Restriction of Fermentable Oligo-, Di- and Mono-

saccharides and Polyols globally, rather than individually, controls the symptoms of functional gut disorders (e.g. IBS), and the majority of IBD patients respond just as well. It is more successful than restricting only Fructose and Fructans, which are also FODMAPs, as is recommended for those with Fructose malabsorption. Longer term compliance with the diet was high.

A randomised controlled trial on IBS patients found relaxing an IgG-mediated food intolerance diet led to a 24% greater deterioration in symptoms compared to those on the elimination diet and concluded food elimination based on IgG antibodies may be effective in reducing IBS symptoms and is worthy of further biomedical research.

Intestinal or bowel hyperpermeability, so called leaky gut, has been linked to food allergies and some food intolerances. Research is currently focussing on specific conditions and effects of certain food constituents. At present there are a number of ways to limit the increased permeability, but additional studies are required to assess if this approach reduces the prevalence and severity of specific conditions.

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.

Postcholecystectomy syndrome describes the presence of abdominal symptoms after surgical removal of the gallbladder (cholecystectomy), 2 years after the surgery.

Symptoms of postcholecystectomy syndrome may include:

- Dyspepsia, nausea, and vomiting.

- Flatulence, bloating, and diarrhea.

- Persistent pain in the upper right abdomen.

Symptoms occur in about 5 to 40 percent of patients who undergo cholecystectomy, and can be transient, persistent or lifelong. The chronic condition is diagnosed in approximately 10% of postcholecystectomy cases.

The pain associated with postcholecystectomy syndrome is usually ascribed to either sphincter of Oddi dysfunction or to post-surgical adhesions. A recent study shows that postcholecystectomy syndrome can be caused by biliary microlithiasis.

Approximately 50% of cases are due to biliary causes such as remaining stone, biliary injury, dysmotility, and choledococyst. The remaining 50% are due to non-biliary causes. This is because upper abdominal pain and gallstones are both common but are not always related.

Chronic diarrhea in postcholecystectomy syndrome is a type of bile acid diarrhea (type 3). This can be treated with a bile acid sequestrant like cholestyramine, colestipol or colesevelam, which may be better tolerated.

Underlying causes include gastric ulcers, duodenal ulcers, appendicitis, gastrointestinal cancer, diverticulitis, inflammatory bowel disease, superior mesenteric artery syndrome, trauma and ascariasis. Typhoid fever, non-steroidal anti-inflammatory drugs, ingestion of corrosives may also be responsible.

The prognosis of children diagnosed with intolerance to milk is good: patients respond to diet which excludes cow's milk protein and the majority of patients succeed in forming tolerance. Children with non-IgE-mediated cows milk intolerance have a good prognosis, whereas children with IgE-mediated cows milk allergy in early childhood have a significantly increased risk for persistent allergy, development of other food allergies, asthma and rhinoconjunctivitis.

A study has demonstrated that identifying and appropriately addressing food sensitivity in IBS patients not previously responding to standard therapy results in a sustained clinical improvement and increased overall well being and quality of life.

Functional somatic syndromes may occur in 6 to 36% of the population.

Dysmenorrhea is estimated to affect approximately 25% of women. Reports of dysmenorrhea are greatest among individuals in their late teens and 20s, with reports usually declining with age. The prevalence in adolescent females has been reported to be 67.2% by one study and 90% by another. It has been stated that there is no significant difference in prevalence or incidence between races. Yet, a study of Hispanic adolescent females indicated a high prevalence and impact in this group. Another study indicated that dysmenorrhea was present in 36.4% of participants, and was significantly associated with lower age and lower parity. Childbearing is said to relieve dysmenorrhea, but this does not always occur. One study indicated that in nulliparous women with primary dysmenorrhea, the severity of menstrual pain decreased significantly after age 40. A questionnaire concluded that menstrual problems, including dysmenorrhea, were more common in females who had been sexually abused.

A survey in Norway showed that 14 percent of females between the ages of 20 to 35 experience symptoms so severe that they stay home from school or work. Among adolescent girls, dysmenorrhea is the leading cause of recurrent short-term school absence.

Psychological trauma or stress appears to predispose persons to a functional somatic syndrome. HPA axis, autonomic nervous system, and immune response to stress has been proposed as a mediating mechanism. Upper airway resistance syndrome may also be implicated.

Dysmenorrhea can be classified as either primary or secondary based on the absence or presence of an underlying cause. Secondary dysmenorrhea is dysmenorrhea which is associated with an existing condition.

The most common cause of secondary dysmenorrhea is endometriosis, which can be visually confirmed by laparoscopy in approximately 70% of adolescents with dysmenorrhea.

Other causes of secondary dysmenorrhea include leiomyoma, adenomyosis, ovarian cysts, and pelvic congestion.

Unequal leg length might hypothetically be one of the contributors, as it may contribute to a tilted pelvis, which may cause lower back pain, which in turn may be mistaken for menstrual pain, as women with lower back pain experience increased pain during their periods.

Other skeletal abnormalities, such as scoliosis (sometimes caused by spina bifida) might be possible contributors as well.

A person with well-treated PA can live a healthy life. Failure to diagnose and treat in time, however, may result in permanent neurological damage, excessive fatigue, depression, memory loss, and other complications. In severe cases, the neurological complications of pernicious anemia can lead to death - hence the name, "", meaning deadly.

An association has been observed between pernicious anemia and certain types of gastric cancer, but a causal link has not been established.

PA is estimated to affect 0.1% of the general population and 1.9% of those over 60, accounting for 20–50% of B deficiency in adults. A review of literature shows that the prevalence of PA is higher in Northern Europe, especially in Scandinavian countries, and among people of African descent, and that increased awareness of the disease and better diagnostic tools might play a role in apparently higher rates of incidence.

From 1869, neurasthenia became a "popular" diagnosis, expanding to include such symptoms as weakness, dizziness and fainting, and a common treatment was the rest cure, especially for women, who were the gender primarily diagnosed with this condition at that time. Recent analysis, however, of data from this period gleaned from the Annual Reports of Queen Square Hospital, London, indicates that the diagnosis was more evenly balanced between the sexes than is commonly thought. Virginia Woolf was known to have been forced to have rest cures, which she describes in her book "On Being Ill". Charlotte Perkins Gilman's protagonist in "The Yellow Wallpaper" also suffers under the auspices of rest cure doctors, much as Gilman herself did. Marcel Proust was said to suffer from neurasthenia. To capitalize on this epidemic, the Rexall drug company introduced a medication called 'Americanitis Elixir' which claimed to be a soother for any bouts related to Neurasthenia.

Neurasthenia is a term that was first used at least as early as 1829 to label a mechanical weakness of the "nerves" and would become a major diagnosis in North America during the late nineteenth and early twentieth centuries after neurologist George Miller Beard reintroduced the concept in 1869.

As a psychopathological term, the first to publish on neurasthenia was Michigan alienist E. H. Van Deusen of the Kalamazoo asylum in 1869, followed a few months later by New York neurologist George Beard, also in 1869 to denote a condition with symptoms of fatigue, anxiety, headache, heart palpitations, high blood pressure, neuralgia, and depressed mood. Van Deusen associated the condition with farm wives made sick by isolation and a lack of engaging activity, while Beard connected the condition to busy society women and overworked businessmen.

Neurasthenia is currently a diagnosis in the World Health Organization's International Classification of Diseases (and the Chinese Society of Psychiatry's Chinese Classification of Mental Disorders). However, it is no longer included as a diagnosis in the American Psychiatric Association's "Diagnostic and Statistical Manual of Mental Disorders".

Americans were said to be particularly prone to neurasthenia, which resulted in the nickname "Americanitis" (popularized by William James). Another, rarely used, term for neurasthenia is nervosism.

Low blood pressure can be caused by low blood volume, hormonal changes, widening of blood vessels, medicine side effects, anemia, heart problems or endocrine problems.

Reduced blood volume, hypovolemia, is the most common cause of hypotension. This can result from hemorrhage; insufficient fluid intake, as in starvation; or excessive fluid losses from diarrhea or vomiting. Hypovolemia is often induced by excessive use of diuretics. Low blood pressure may also be attributed to heat stroke. The body may have enough fluid but does not retain electrolytes. Absence of perspiration, light headedness and dark coloured urine are also indicators.

Other medications can produce hypotension by different mechanisms. Chronic use of alpha blockers or beta blockers can lead to hypotension. Beta blockers can cause hypotension both by slowing the heart rate and by decreasing the pumping ability of the heart muscle.

Decreased cardiac output despite normal blood volume, due to severe congestive heart failure, large myocardial infarction, heart valve problems, or extremely low heart rate (bradycardia), often produces hypotension and can rapidly progress to cardiogenic shock. Arrhythmias often result in hypotension by this mechanism.

Some heart conditions can lead to low blood pressure, including extremely low heart rate (bradycardia), heart valve problems, heart attack and heart failure. These conditions may cause low blood pressure because they prevent the body from being able to circulate enough blood.

Excessive vasodilation, or insufficient constriction of the resistance blood vessels (mostly arterioles), causes hypotension. This can be due to decreased sympathetic nervous system output or to increased parasympathetic activity occurring as a consequence of injury to the brain or spinal cord or of dysautonomia, an intrinsic abnormality in autonomic system functioning. Excessive vasodilation can also result from sepsis, acidosis, or medications, such as nitrate preparations, calcium channel blockers, or AT1 receptor antagonists (Angiotensin II acts on AT1 receptors). Many anesthetic agents and techniques, including spinal anesthesia and most inhalational agents, produce significant vasodilation.

Meditation, yoga, or other mental-physiological disciplines may reduce hypotensive effects.

Lower blood pressure is a side effect of certain herbal medicines, which can also interact with hypotensive medications. An example is the theobromine in "Theobroma cacao", which lowers blood pressure through its actions as both a vasodilator and a diuretic, and has been used to treat high blood pressure.

Orthostatic hypotension, also called "postural hypotension", is a common form of low blood pressure. It occurs after a change in body position, typically when a person stands up from either a seated or lying position. It is usually transient and represents a delay in the normal compensatory ability of the autonomic nervous system. It is commonly seen in hypovolemia and as a result of various medications. In addition to blood pressure-lowering medications, many psychiatric medications, in particular antidepressants, can have this side effect. Simple blood pressure and heart rate measurements while lying, seated, and standing (with a two-minute delay in between each position change) can confirm the presence of orthostatic hypotension. Orthostatic hypotension is indicated if there is a drop in 20 mmHg of systolic pressure (and a 10 mmHg drop in diastolic pressure in some facilities) and a 20 beats per minute increase in heart rate.

Vasovagal syncope is a form of dysautonomia characterized by an inappropriate drop in blood pressure while in the upright position. Vasovagal syncope occurs as a result of increased activity of the vagus nerve, the mainstay of the parasympathetic nervous system .

Another, but rarer form, is postprandial hypotension, a drastic decline in blood pressure that occurs 30 to 75 minutes after eating substantial meals. When a great deal of blood is diverted to the intestines (a kind of "splanchnic blood pooling") to facilitate digestion and absorption, the body must increase cardiac output and peripheral vasoconstriction to maintain enough blood pressure to perfuse vital organs, such as the brain. Postprandial hypotension is believed to be caused by the autonomic nervous system not compensating appropriately, because of aging or a specific disorder.

Hypotension is a feature of Flammer syndrome which is characterized by cold hands and feet and predisposes to normal tension glaucoma.

Menorrhagia is a menstrual period with excessively heavy flow and falls under the larger category of abnormal uterine bleeding (AUB).

Abnormal uterine bleeding can be caused by structural abnormalities in the reproductive tract, anovulation, bleeding disorders, hormone issues (such as hypothyroidism) or cancer of the reproductive tract. Initial evaluation aims at figuring out pregnancy status, menopausal status, and the source of bleeding.

Treatment depends on the cause, severity, and interference with quality of life. Initial treatment often involve contraceptive pills. Surgery can be an effective second line treatment for those women whose symptoms are not well-controlled. Approximately 53 in 1000 women are affected by AUB.