Symptom Checker: Symptoms & Signs Index
Medical Author: William C. Shiel Jr., MD, FACP, FACR
Gas or "intestinal gas" means different things to different people. Everyone has gas and eliminates it by belching or farting (passing it through the rectum).
The ability to belch is almost universal. Belching, also known as burping, is the act of expelling gas from the stomach out through the mouth. The usual cause of belching is a distended (inflated) stomach caused by swallowed air. The distention of the stomach causes abdominal discomfort, and the belching expels the air and relieves the discomfort. The common reasons for swallowing large amounts of air (aerophagia) are gulping food or drink too rapidly, anxiety, and carbonated beverages.
Excessive air in the stomach is not the only cause of belching. For some people, belching becomes a habit and does not reflect the amount of air in their stomachs. For others, belching is a response to any type of abdominal discomfort and not just to discomfort due to increased gas.
Most people produce 1 to 3 pints of intestinal gas in their large intestines (colons) every 24 hours and pass gas an average of 14 times a day. The gas is made up primarily of carbon dioxide, hydrogen, and in some families, methane, that is mixed with nitrogen and oxygen from room air that is inhaled or swallowed. The carbon dioxide, hydrogen, and methane are produced by bacteria in the large intestine while they digest undigested food that reaches the large intestine. Although these gases are odorless, the bacteria also may produce small amounts of sulfur-containing gases that are foul-smelling. It is important to distinguish between increased flatulence (farting) and foul-smelling flatulence.
Bloating is the subjective sensation (feeling) that the abdomen is larger than normal. Thus, bloating is a symptom akin to the symptom of discomfort. In contrast, distention is the objective determination (physical finding) that the abdomen is actually larger than normal. Bloating and distention may be due to increased amounts of gas in the abdomen, but there also are other causes.
Health concern on your mind? Visit the Symptom Checker.
Fauci, Anthony S., et al. Harrison's Principles of Internal Medicine. 17th ed. United States: McGraw-Hill Professional, 2008.
Causes of Gas
In This ArticleCeliac Disease Article
- Celiac disease definition
- What causes celiac disease?
- What are the signs and symptoms of celiac disease?
- Are there other diseases or conditions associated with celiac disease?
- How is celiac disease diagnosed?
- What is latent celiac disease?
- What is silent celiac disease?
- What is the treatment for celiac disease?
- What is refractory celiac disease?
- What is the treatment for refractory celiac disease?
- What are the complications of celiac disease?
- What is a gluten-free diet?
In This ArticleGastroparesis Article
- Gastroparesis facts
- What is gastroparesis?
- What causes gastroparesis?
- What are gastroparesis symptoms and signs?
- How is gastroparesis diagnosed?
- How is gastroparesis treated?
- What is the prognosis (long-term outcome) for patients with gastroparesis?
- What's new in gastroparesis?
In This ArticleIndigestion (Dyspepsia, Upset Stomach) Article
- What is dyspepsia (indigestion)?
- What are the symptoms of dyspepsia (indigestion)?
- What causes dyspepsia (indigestion)?
- What is the course of dyspepsia (indigestion)?
- What are the complications of dyspepsia (indigestion)?
- How is dyspepsia (indigestion) diagnosed?
- Exclusion of other diseases
- Specific tests of gastrointestinal function
- How is dyspepsia (indigestion) treated?
- What is a reasonable approach to the diagnosis and treatment of dyspepsia (indigestion)?
- What is in the future for dyspepsia (indigestion)?
- Dyspepsia (Indigestion) At A Glance
In This ArticleIrritable Bowel Syndrome (IBS) Article
- Irritable bowel syndrome (IBS) definition
- What causes irritable bowel syndrome (IBS)?
- What are the symptoms of irritable bowel syndrome (IBS)?
- How is the diagnosis of irritable bowel syndrome (IBS) made?
- What are the treatments for irritable bowel syndrome (IBS)?
- What medications are used to treat irritable bowel syndrome (IBS)?
- What about IBS and diet?
- Is irritable bowel syndrome (IBS) related to small bacterial overgrowth (SIBO)?
- What is the prognosis for irritable bowel syndrome (IBS)?
In This ArticleLactose Intolerance Article
- Lactose intolerance facts
- What is lactose intolerance?
- What causes lactose intolerance?
- What are the symptoms of lactose intolerance?
- How are lactase deficiency and lactose intolerance diagnosed?
- Elimination diet
- Milk challenge
- Breath test
- Blood glucose test
- Stool acidity test
- What are the sources of lactose in the diet?
- How is lactose intolerance treated?
- What are the long-term consequences of lactose intolerance?
- What is new in lactose intolerance?
Other Causes of Gas
- Dietary Fat, Starchy Grains
- Digestive Disease
- Intestinal Blockage
- Pancreatic Insufficiency
Examples of Medications for Gas
Get the latest treatment options.