Abdominal bloating (or simply bloating) is a short-term disease that affects the gastrointestinal tract. Bloating is generally characterized by an excess buildup of gas, air or fluids in the

stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...

. A person may have feelings of tightness, pressure or fullness in the stomach; it may or may not be accompanied by a visibly distended abdomen. Bloating can affect anyone of any age range and is usually self-diagnosed, in most cases does not require serious medical attention or treatment. Although this term is usually used interchangeably with abdominal distension, these symptoms probably have different pathophysiological processes, which are not fully understood. The first step for the management is to find a treatment for the underlying causes that produce it through a detailed medical history and a physical examination. The discomfort can be alleviated by the use of certain drugs and dietary modifications. Bloating can also be caused by chronic conditions and in rare cases can be a reoccurring life-threatening problem.

Symptoms and signs

The most common symptom associated with bloating is a sensation that the abdomen is full or distended. Rarely, bloating may be painful or cause shortness of breath. Pains that are due to bloating will feel sharp and cause the stomach to

cramp A cramp is a sudden, involuntary, painful skeletal muscle contraction or overshortening associated with electrical activity; while generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the aff ...

. These pains may occur anywhere in the body and can change locations quickly. They are so painful that they are sometimes mistaken for heart pains when they develop on the upper left side of the chest. Pains on the right side are often confused with problems in the appendix or the

gallbladder In vertebrates, the gallbladder, also known as the cholecyst, is a small hollow organ where bile is stored and concentrated before it is released into the small intestine. In humans, the pear-shaped gallbladder lies beneath the liver, although ...

. One symptom of gas that is not normally associated with it is the

hiccup A hiccup (scientific name ''singultus'', from a Latin word meaning "to catch one's breath while sobbing"; also spelled hiccough) is an involuntary contraction ( myoclonic jerk) of the diaphragm that may repeat several times per minute. The hi ...

. Hiccups are harmless and will diminish on their own; they also help to release gas that is in the

digestive tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

before it moves down to the intestines and causes bloating. Important but uncommon causes of abdominal bloating include

ascites Ascites is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdominal size, increased weight, a ...

and tumors.

Causes

There are many causes of bloating, including: diet,

irritable bowel syndrome Irritable bowel syndrome (IBS) is a "disorder of gut-brain interaction" characterized by a group of symptoms that commonly include abdominal pain and or abdominal bloating and changes in the consistency of bowel movements. These symptoms may ...

lactose intolerance Lactose intolerance is a common condition caused by a decreased ability to digest lactose, a sugar found in dairy products. Those affected vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pai ...

reflux Reflux is a technique involving the condensation of vapors and the return of this condensate to the system from which it originated. It is used in industrial and laboratory distillations. It is also used in chemistry to supply energy to reactions ...

, and

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...

. Specific medical conditions like Crohn's disease or bowel obstruction can also contribute to the amount of stomach bloating experienced. Common causes of abdominal bloating are: *

Overeating Overeating occurs when an individual consumes more calories in relation to the energy that is expended via physical activity or expelled via excretion, leading to weight gain and often obesity. Overeating is the defining characteristic of bing ...

Gastric distension Gastric distention is the enlargement of the stomach, and can be due to a number of causes. Physiologic (normal) gastric distension occurs when eating. Distension of the upper stomach stimulates the secretion of stomach acid, while distension of t ...

Lactose intolerance Lactose intolerance is a common condition caused by a decreased ability to digest lactose, a sugar found in dairy products. Those affected vary in the amount of lactose they can tolerate before symptoms develop. Symptoms may include abdominal pai ...

, fructose intolerance and other

food intolerance Food intolerance is a detrimental reaction, often delayed, to a food, beverage, food additive, or compound found in foods that produces symptoms in one or more body organs and systems, but generally refers to reactions other than food allergy. Fo ...

s * Premenstrual syndrome *

Food allergy A food allergy is an abnormal immune response to food. The symptoms of the allergic reaction may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressur ...

Aerophagia Aerophagia (or aerophagy) is a condition of excessive air swallowing, which goes to the stomach instead of the lungs. Aerophagia may also refer to an unusual condition where the primary symptom is excessive flatus (farting), belching (burping) is ...

(air swallowing, a nervous habit) *

Irritable bowel syndrome Irritable bowel syndrome (IBS) is a "disorder of gut-brain interaction" characterized by a group of symptoms that commonly include abdominal pain and or abdominal bloating and changes in the consistency of bowel movements. These symptoms may ...

Celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barle ...

Non-celiac gluten sensitivity Non-celiac gluten sensitivity (NCGS) or gluten sensitivity is "a clinical entity induced by the ingestion of gluten leading to intestinal and/or extraintestinal symptoms that improve once the gluten-containing foodstuff is removed from the diet, a ...

* Partial bowel obstruction *

Gastric dumping syndrome Dumping syndrome occurs when food, especially sugar, moves too quickly from the stomach to the duodenum—the first part of the small intestine—in the upper gastrointestinal (GI) tract. This condition is also called rapid gastric emptying. It i ...

or rapid gastric emptying * Gas-producing foods *

Constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...

Visceral fat Adipose tissue, body fat, or simply fat is a loose connective tissue composed mostly of adipocytes. In addition to adipocytes, adipose tissue contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular e ...

* Splenic-flexure syndrome * Menstruation, dysmenorrhea *

Polycystic ovary syndrome Polycystic ovary syndrome, or PCOS, is the most common endocrine disorder in women of reproductive age. The syndrome is named after the characteristic cysts which may form on the ovaries, though it is important to note that this is a sign and no ...

and

ovarian cyst An ovarian cyst is a fluid-filled sac within the ovary. Often they cause no symptoms. Occasionally they may produce bloating, lower abdominal pain, or lower back pain. The majority of cysts are harmless. If the cyst either breaks open or causes ...

s *

Alvarez' syndrome Alvarez' syndrome is a medical disorder in which the abdomen becomes bloated without any obvious reason, such as intestinal gas Flatulence, in humans, is the expulsion of gas from the intestines via the anus, commonly referred to as farting. ...

, bloating of unknown or psychogenic origin without excess gas in the digestive tract * Massive infestation with

intestinal parasite An intestinal parasite infection is a condition in which a parasite infects the gastro-intestinal tract of humans and other animals. Such parasites can live anywhere in the body, but most prefer the intestinal wall. Routes of exposure and inf ...

s (e.g., ''

Ascaris lumbricoides ''Ascaris lumbricoides'' is a large parasitic worm that causes ascariasis in humans. A roundworm of genus '' Ascaris'', it is the most common parasitic worm in humans. An estimated one-sixth of the human population is at some point infected by ...

'') * Diverticulosis * Certain medications, such as

phentermine Phentermine ( phenyl- tertiary-butyl amine), with several brand names including Ionamin and Sentis, is a medication used together with diet and exercise to treat obesity. It is taken by mouth for up to a few weeks at a time, after which the ben ...

* Occurs in some due to

salivary The salivary glands in mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands (parotid, submandibular, and sublingual), as well as hundreds of minor salivary glands. Salivary glan ...

hypersecretion and

dehydration In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...

. *

Ovarian cancer Ovarian cancer is a cancerous tumor of an ovary. It may originate from the ovary itself or more commonly from communicating nearby structures such as fallopian tubes or the inner lining of the abdomen. The ovary is made up of three different c ...

Important but uncommon causes of abdominal bloating include: * Large cancerous intra-abdominal

tumors A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

of the ovary,

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it ...

uterus The uterus (from Latin ''uterus'', plural ''uteri'') or womb () is the organ in the reproductive system of most female mammals, including humans that accommodates the embryonic and fetal development of one or more embryos until birth. The ...

and

Megacolon Megacolon is an abnormal dilation of the colon (also called the large intestine). This leads to hypertrophy of the colon. The dilation is often accompanied by a paralysis of the peristaltic movements of the bowel. In more extreme cases, the feces ...

, an abnormal dilation of the colon caused by some diseases, such as Chagas disease, a

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

infection *

Cardiopulmonary resuscitation Cardiopulmonary resuscitation (CPR) is an emergency procedure consisting of chest compressions often combined with artificial ventilation in an effort to manually preserve intact brain function until further measures are taken to restore spon ...

procedures, due to the artificial mouth-to-mouth insufflation of air. In animals, causes of abdominal bloating include: *

Gastric dilatation volvulus Gastric dilatation volvulus (GDV), also known as gastric dilation, twisted stomach, or gastric torsion, is a medical condition that affects dogs in which the stomach becomes overstretched and rotated by excessive gas content. The word bloat is o ...

, a condition of dogs which occurs when gas is trapped inside the stomach and gastric torsion prevents it from escaping *

Ruminal tympany Ruminal tympany, also known as ruminal bloat, is a disease of ruminant animals, characterized by an excessive volume of gas in the rumen. Ruminal tympany may be primary, known as frothy bloat, or secondary, known as free-gas bloat. In the rumen, fo ...

, a condition of ruminant animals which occurs when gas cannot escape from the rumen. All the factors mentioned contribute to bloated stomach abdominal pain. Every person produces gases in their body during the digestion of food, such as methane, hydrogen, carbon dioxide, and nitrogen. And some of them are released outside the body, sometimes in small quantities that one does not notice and sometimes in larger quantities that may affect the normal course of life.

Fiber

Most cases of stomach bloating are due to improper

diet Diet may refer to: Food * Diet (nutrition), the sum of the food consumed by an organism or group * Dieting, the deliberate selection of food to control body weight or nutrient intake ** Diet food, foods that aid in creating a diet for weight loss ...

. Gas occurs because of the bacteria in the colon and is a by-product of soluble fiber digestion. Inadequate or irregular intake of fiber and water will cause a person to experience bloating or constipation. The most common natural sources of fiber include fruits and vegetables as well as wheat or oat bran. These fibers are most likely to cause flatulence. Fiber is made by plants and is not easily digested by the

human gastrointestinal tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...

. There are two main types of dietary fiber: soluble and insoluble fiber. Soluble fiber is prebiotic and readily fermented in the colon into gases, while insoluble fiber is metabolically inert and absorbs water as it moves through the digestive system, aiding in defecation. Most types of fiber (insoluble) are attached to

body water In physiology, body water is the water content of an animal body that is contained in the tissues, the blood, the bones and elsewhere. The percentages of body water contained in various fluid compartments add up to total body water (TBW). This ...

in the intestine and increase the volume of stools.

Bowel gas

Gas in the gastrointestinal tract has only two sources. It is either swallowed air or is produced by bacteria that normally inhabit the intestines, primarily the colon.

Belching Burping (also called belching and eructation) is the release of gas from the upper digestive tract (esophagus and stomach) of animals through the mouth. It is usually audible. In humans, burping can be caused by normal eating processes, or as ...

or burping is a universal ability that works by removing gas from the stomach through the mouth. The stomach can become bloated when too much air is swallowed during eating and drinking too quickly. As the stomach swells, belching removes the gas and alleviates the pain associated with it. Burping can also be used as a form of relief from abdominal discomfort other than too much gas in the stomach. Flatulence, or farting, provides relief of much the same kind as burping, but involves the passage of gas from the body via the anus, not the mouth. Bacteria present in the intestinal tract cause gas that is expelled from the anus. They produce the gas as food is digested and moved from the small intestine. This gas builds up and causes swelling or bloating in the abdominal area before it is released.

Constipation

A common gastrointestinal problem is

—infrequent bowel movements, hard stools, or strain during the movements—which causes serious cases of bloating. Since most cases of constipation are temporary, simple lifestyle changes, such as getting more exercise and increasing one's intake of fiber, can contribute to alleviating constipation. Some cases of constipation will continue to worsen and require unconventional methods to release the feces and reduce the amount of stomach bloating. Blood in the stool, intense pain in the abdomen, rectal pain, unexplained weight loss, and continued bloating and constipation not relieved by the above lifestyle changes should be reported to a doctor. Bloating consistently accompanies constipation, and they will not develop without an underlying cause.

Heartburn and acid reflux

Painful burning sensations in the chest that are caused by gastroesophageal reflux is known as

heartburn Heartburn, also known as pyrosis, cardialgia or acid indigestion, is a burning sensation in the central chest or upper central abdomen. Heartburn is usually due to regurgitation of gastric acid (gastric reflux) into the esophagus. It is the m ...

. Reflux is the backflow of gastric acid juices from the stomach into the

oesophagus The esophagus (American English) or oesophagus (British English; both ), non-technically known also as the food pipe or gullet, is an organ in vertebrates through which food passes, aided by peristaltic contractions, from the pharynx to th ...

. Heartburn has different triggers, including certain foods, medications,

obesity Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ...

, and stress. These triggers are different for each individual.

Gastroesophageal reflux disease Gastroesophageal reflux disease (GERD) or gastro-oesophageal reflux disease (GORD) is one of the upper gastrointestinal chronic diseases where stomach content persistently and regularly flows up into the esophagus, resulting in symptoms and/ ...

or GERD is a chronic condition that can lead to more serious complications like esophageal cancer. Treatment options are available to treat the symptoms and the condition, but there is no cure for the disease. Symptoms include burping, abdominal and stomach bloating, along with pain and discomfort. Heavy meals, lying down or bending over after eating should be avoided to help prevent reflux from occurring. The stomach bloating experienced with reflux is intense and will remain until the food is digested all the way. Postmortem bloating occurs in cadavers, due to the formation of gases by

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometr ...

l action and

putrefaction Putrefaction is the fifth stage of death, following pallor mortis, algor mortis, rigor mortis, and livor mortis. This process references the breaking down of a body of an animal, such as a human, post-mortem. In broad terms, it can be view ...

of the internal tissues of the abdomen and the inside of the intestines.

Related conditions

Conditions that are related to bloating include constipation, lactose intolerance, and

acid reflux Gastroesophageal reflux disease (GERD) or gastro-oesophageal reflux disease (GORD) is one of the upper gastrointestinal chronic diseases where stomach content persistently and regularly flows up into the esophagus, resulting in symptoms and/ ...

disease. All of these conditions share the same symptoms and can share the same causative agents. These causes include unhealthy diet, smoking, alcohol consumption, low amount of exercise, and overall health. Each of these conditions can be experienced as a symptom of the others and is also a cause for each of them. In most cases where one of the conditions is present, there is at least one if not two of the others. Treatment for each condition is performed using the same medications and recommended dietary changes like increased fiber intake and reduced fat intake. If the conditions develop into diseases such as gastroesophageal reflux disease or chronic constipation, additional medications will be required. Bloating and flatulence are sometimes related to constipation, and treating the underlying condition may be helpful.

Treatment

Diets

Promising evidence on the potential efficacy of the low-FODMAP diet in functional abdominal bloating is provided by the reduction of the bloating which has been observed in some studies on patients with

. Regarding the

gluten-free diet A gluten-free diet (GFD) is a nutritional plan that strictly excludes gluten, which is a mixture of proteins found in wheat (and all of its species and hybrids, such as spelt, kamut, and triticale), as well as barley, rye, and oats. The incl ...

, there is insufficient scientific evidence to recommend it to reduce bloating and abdominal distension. As regards the FODMAP diet, this should be provided by experts in nutrition to reduce the risks associated with elimination diets.Pessarelli, T., Sorge, A., Elli, L., & Costantino, A. The Gluten-free Diet and the Low-FODMAP Diet in the Management of Functional Abdominal Bloating and Distension. Frontiers in Nutrition, 2680.

Medications

There are many

over-the-counter Over-the-counter (OTC) drugs are medicines sold directly to a consumer without a requirement for a prescription from a healthcare professional, as opposed to prescription drugs, which may be supplied only to consumers possessing a valid prescr ...

(OTC) medications that can be used to treat bloating. Food

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

s can be found in some products that will help break down the sugars found in grains, vegetables and dairy products. They can be taken before food is consumed or added to the food that causes the gas and bloating. The most common treatment is

antacid An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhea. Marketed antacids contain salts of alu ...

s. These medications have no effect on the gas that is present in the intestines but enable gas build-up to be belched away more easily, reducing the amount of bloating that develops. Another treatment is

simethicone Simeticone ( INN), also known as simethicone (USAN), is an anti-foaming agent used to reduce bloating, discomfort or pain caused by excessive gas. Medical uses Simeticone is used to relieve the symptoms of excessive gas in the gastrointestina ...

, an oral anti-foaming agent that helps the body to expel the gas more quickly. Combinations of

prokinetics A prokinetic agent (also gastroprokinetic agent, gastrokinetic agent or propulsive) is a type of drug which enhances gastrointestinal motility by increasing the frequency or strength of contractions, but without disrupting their rhythm. They are us ...

, such as

domperidone Domperidone, sold under the brand name Motilium among others, is a dopamine antagonist medication which is used to treat nausea and vomiting and certain gastrointestinal problems like gastroparesis (delayed gastric emptying). It raises the le ...

metoclopramide Metoclopramide is a medication used for stomach and esophageal problems. It is commonly used to treat and prevent nausea and vomiting, to help with emptying of the stomach in people with delayed stomach emptying, and to help with gastroesoph ...

diphenhydramine Diphenhydramine (DPH) is an antihistamine and sedative mainly used to treat allergies, insomnia, and symptoms of the common cold. It is also less commonly used for tremor in parkinsonism, and nausea. It is taken by mouth, injected into ...

(the latter for the prevention of extrapyramidal reactions, especially acute dystonic reactions) +

proton pump inhibitors Proton-pump inhibitors (PPIs) are a class of medications that cause a profound and prolonged reduction of stomach acid production. They do so by irreversibly inhibiting the stomach's H+/K+ ATPase proton pump. They are the most potent inhibitor ...

(PPIs), have dramatic effects on bloaters and belchers especially.

References

Notes Bibliography * Partly based o
Abdominal bloating
MedlinePlus (US public domain Medical Encyclopedia). Update Date: 10 November 2004. Updated by: Christian Stone, M.D., Division of Gastroenterology, Washington University in St. Louis School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network. Ahmed Shazly. * Van Vorous, Heather. ''Eating for IBS''. 2000. . Excerpted with author's permission a
Help for Irritable Bowel Syndrome
(see IBS Diet Section) *(2021, January 16
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