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Gas in the Digestive Tract

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Definition & Facts

A gas is a substance that has no fixed size or shape. The gas inside your digestive tract is made of air and other gases. Gas typically leaves your digestive tract through your mouth when you belch or through your anus when you pass gas.

man suffers from stomachache

Symptoms & Causes

Common symptoms related to gas in the digestive tract include belching, bloating and distention, and passing gas. Gas normally enters your digestive tract when you swallow air and when bacteria in your large intestine break down certain undigested carbohydrates.


Doctors may diagnose the causes of gas with a medical history and physical exam. Doctors may order medical tests if they suspect that certain health conditions may be causing an increase in gas or gas symptoms.


To reduce or prevent excess gas or gas symptoms, your doctor may recommend swallowing less air, changing your eating and drinking habits or diet, or taking medicines or supplements. The medicines or supplements your doctor recommends will depend on your symptoms and health conditions.

Eating, Diet, & Nutrition

If you have problems with gas symptoms, your doctor may recommend changing your eating and drinking habits, changing your diet, or following a special diet to help treat certain health conditions. Talk with your doctor or dietitian about a healthy eating plan that may help with gas symptoms.

Clinical Trials

The NIDDK conducts and supports clinical trials in many diseases and conditions, including digestive diseases. The trials look to find new ways to prevent, detect, or treat disease and improve quality of life.

Your Digestive System & How It Works

The digestive system is made up of the gastrointestinal (GI) tract—also called the digestive tract—and the liver, pancreas, and the gallbladder. The GI tract is a series of hollow organs joined in a long, twisting tube from the mouth to the anus.

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Related Research

Last Reviewed June 2021

This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. NIDDK translates and disseminates research findings to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by NIDDK is carefully reviewed by NIDDK scientists and other experts.

The NIDDK would like to thank:
Brian E. Lacy, Ph.D., M.D., Mayo Clinic, Jacksonville, Florida