Flatulence

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is flatulence?

The flatulence definition is the expulsion of gas (flatus) from the gastrointestinal tract through the rectum. Daily, the average person produces one to four pints of gas and expels it—or "farts"—up to 14 times. Although farting can cause embarrassment to some people, gas and farting are a normal part of digestion.

Eating certain foods or drinking carbonated beverages can introduce air into the stomach and increase gas. You may also swallow air when you eat too quickly, sip beverages through a straw, or when you chew gum. Because infants frequently swallow air when feeding, they may have gas after they have been fed. The act of burping an infant helps relieve the discomfort caused by swallowed air.

Flatulence is also caused by the passage of undigested food from the small intestine to the large intestine. Bacteria in the large intestine process the food and produce harmless gases, such as carbon dioxide, hydrogen, and methane, which are released as gas through the rectum. Certain foods, including carbohydrates, fiber and sugars, are more likely than other foods to produce gas. Flatus odor comes from hydrogen sulfide and other gases containing sulfur.

Other flatulence causes include many different types of gastrointestinal conditions and diseases. Gas and farting may occur with conditions that slow digestion, such as gastroparesis (delayed stomach emptying), and mechanical obstructions, such as pyloric obstruction (blockage between the stomach and small intestine). Pregnant women may also experience flatulence due to hormonal changes that slow the digestive process. Flatulence can also arise from conditions that impair the normal digestive process in other ways, such as acid reflux, hiatal hernia, or stomach acid deficiency.

Flatulence is rarely associated with a medical emergency. Seek immediate medical care (call 911) if your flatulence is associated with severe abdominal pain, chest pain, persistent nausea and vomiting, or high fever (higher than 101°F).

Seek prompt medical care if your flatulence symptoms are persistent or cause you concern.

What other symptoms might occur with flatulence?

Flatulence may be accompanied by other symptoms, depending on the underlying disease, disorder or condition. Symptoms that frequently affect the digestive tract may also involve other body systems.

Digestive symptoms that may occur along with gas

Flatulence may accompany other symptoms affecting the digestive tract including:

  • Belching
  • Change in bowel habits
  • Constipation
  • Diarrhea
  • Farting
  • Nausea with or without vomiting

Other symptoms that may occur along with gas

Flatulence may accompany symptoms related to other body systems. Flatulence can occur as a nervous habit and may be associated with generalized symptoms including:

  • Emotional stress
  • Nervousness

Serious symptoms that might indicate a life-threatening condition

Flatulence is rarely a sign of a medical emergency. In some cases, however, flatulence may occur with other symptoms that might indicate a serious or life-threatening condition that should be immediately evaluated in an emergency setting. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:

  • High fever (higher than 101°F)
  • Severe abdominal pain

What causes flatulence?

Flatulence, farting and belching are natural occurrences that result from eating or drinking too quickly. Eating certain foods or drinking carbonated beverages can also introduce air into the stomach and cause gas. Because infants frequently swallow air when feeding, they may have gas after they have been fed. The act of burping an infant helps relieve the discomfort caused by swallowed air.

Flatulence is also caused by the passage of undigested food from the small intestine to the large intestine. Normal “gut” bacteria produce harmless gases as they process the food. Gas from the rectum includes carbon dioxide, hydrogen sulfide, and methane.

Food causes of gas

Flatulence may be caused by eating certain foods including:

  • Fiber, especially soluble forms of fiber, which passes undigested until it reaches the large intestine
  • Starchy foods, such as breads and rice
  • Sugars, including fructose (found in some foods and sweeteners), lactose (found in dairy products), raffinose (found in Brussels sprouts, broccoli, cabbage, and beans), and sorbitol (found in fruits and artificial sweeteners)

Gastrointestinal causes of gas

Almost any condition affecting the digestive tract can cause flatulence. These include conditions in which the normal movement or flow in the digestive tract is obstructed, interrupted or delayed. Examples include gastroparesis (delayed stomach emptying), intestinal obstruction, hiatal hernia, and gastroesophageal reflux disease (GERD).

In other types of disorders, the enzymes or processes necessary to digest food completely are either deficient or absent. Examples include food intolerance and gallbladder disease.

Conditions that contribute to flatulence include:

  • Food allergies (allergic reactions to certain foods) or food intolerances (difficulty digesting certain foods without symptoms of a food allergy)
  • Gallbladder disease
  • Irritable bowel syndrome (IBS)
  • Malabsorption
  • Pancreatic disease
  • Tumors of the gastrointestinal tract

Serious or life-threatening causes of flatulence

Flatulence is a normal body process that is rarely serious in nature. However, in rare cases, it may be a symptom of a serious or life-threatening condition that should be evaluated immediately in an emergency setting. These include:

  • Obstruction of the digestive tract

When should you see a doctor for flatulence?

Gas production and farting can cause discomfort and embarrassment, but it is not usually from serious problems. Make an appointment to see your doctor if flatulence interferes with daily life because it is severe, persistent, painful or bothersome. The solution may be as simple as changing your diet.

Sometimes, gas along with other symptoms can indicate a more concerning condition. See a doctor promptly for gas with any of these additional symptoms:

  • Bloody, oily or foul-smelling stools
  • Change in bowel habits
  • Heartburn, stomach pain, nausea or vomiting that persists or occurs on a regular basis
  • Rectal pain

Call 911 or go to your nearest emergency room for gas when:

How do doctors diagnose the cause of flatulence?

To diagnose the cause of abnormal or excessive flatulence, your doctor will take a medical history, review your diet, perform a physical exam, and perhaps order testing. Keeping a symptom diary can be helpful in answering questions during the appointment.

Questions for diagnosing the cause of flatulence

Questions your doctor may ask include:

  • How long have you experienced flatulence?
  • How severe is your gas and how often is it a problem?
  • Is your flatulence becoming worse or more frequent? 
  • What foods do you eat on a regular basis?
  • How fast do you usually eat?
  • Have you changed your diet recently?
  • Does your gas worsen when you consume certain foods or drinks, such as dairy products?
  • Do you use artificial sweeteners, including gum or candy with artificial sweeteners?
  • Are you experiencing any other symptoms, such as diarrhea or cramping, along with your flatulence?
  • What, if anything, seems to improve your flatulence?
  • What medicines do you take?

Physical exam and tests for diagnosing the cause of gas

The physical exam will likely focus on your abdomen. Your doctor may feel your abdomen and listen to it with a stethoscope. This helps your doctor understand if your digestive tract is functioning normally. When feeling your belly, the doctor may tap on it and ask about pain, tenderness or bloating.

Depending on the results of the exam and the questions, your doctor may order testing including:

  • Endoscopy, colonoscopy or sigmoidoscopy to examine the inside of the upper GI tract, colon, or rectum

It is not always possible to diagnose an underlying cause or condition. If the gas problem persists and your provider is unable to determine a cause, seeking a second opinion may give you more information and answers.

How do you treat flatulence?

Prescription medications may be necessary if your doctor diagnoses a condition, such as irritable bowel syndrome (IBS) or gastroesophageal reflux disease (GERD) as a cause of excessive gas. Otherwise, flatulence treatment usually involves over-the-counter medicines including:

  • Activated charcoal (Actidose-Aqua, CharcoCaps, others), which traps gas molecules. However, it can also trap medications and interfere with their absorption. So, talk with your doctor before using it. You take it before and after eating.
  • Alpha-galactosidase (Beano, BeanAssist, Gas-Zyme, others), which is an enzyme that breaks down gas-producing sugars and carbohydrates in beans, grains and vegetables. You take it right before eating.
  • Bismuth subsalicylate (Pepto-Bismol), which can reduce noxious odors from the breakdown of hydrogen sulfide. 
  • Lactase (Dairy Ease, Lactaid, others), which is an enzyme that breaks down lactose. It helps when people are lactose intolerant. You use it just before having dairy products. As an alternative, lactose-free dairy products are also available.
  • Simethicone (Gas-X, Mylanta Gas, others), which reduces the surface tension of gas bubbles to help them break easier. This allows gas to pass through the digestive tract and relieves gas. 

Alternative treatments for flatulence

One of the main alternative treatments for digestive health are probiotics. These healthy bacteria are present in yogurt and fermented foods, such as kimchi. Supplements are also available. Using probiotics to replace and replenish the bacterial flora in your digestive tract may initially increase the frequency of flatulence, but, over time, will significantly help reduce gas, bloating and farting.

What are the diet and lifestyle tips for reducing flatulence?

Diet and lifestyle changes can be very effective in treating flatulence. As you make changes, it can help to keep a symptom diary to see which ones make a difference.

One of the most important aspects is diet and eating habits. Eating a low FODMAP diet can be helpful. FODMAPs are fermentable oligo-, di-, and mono-saccharides and polyols. These short-chain carbohydrates are poorly digestible and absorbable. Instead, they ferment and produce gas. Examples of foods with high FODMAPs include fruits, vegetables, wheat and rye products, dairy, and certain sweeteners.

Experts recommend reducing, avoiding, or eating smaller portions of the following:

  • Artificial sweeteners and sugar substitutes, such as sorbitol
  • Carbonated beverages, which contain gases
  • Dairy that contains lactose. Try lactose-free dairy instead to get the benefits of consuming dairy products. 
  • Fatty or fried foods, which can cause bloating and discomfort
  • High-fiber foods, such as beans, cruciferous vegetables, onions, prunes, and whole grains. Adding them back in gradually after two weeks can help you identify problematic ones. It also helps reduce gas. Talk with your doctor before eliminating high-fiber foods.

Drink plenty of water throughout the day and with your meals. It will help prevent constipation and keep things moving through your digestive tract.

Regular exercise can also help reduce the risk of constipation and aid digestion. Try walking for 10 to 15 minutes after eating.

Other home remedies focus on reducing the amount of air you swallow. Strategies include:

  • Avoiding gulping or drinking through a straw
  • Eating slowly and chewing food thoroughly
  • Not chewing gum or sucking on hard candy 

What are the potential complications of flatulence?

Flatulence is generally a harmless symptom that does not produce long-term complications. However, some of the gastrointestinal conditions associated with flatulence may have serious complications as a result of the underlying disease rather than the symptom of flatulence itself. For example, intestinal obstruction due to cancer is a condition that can have long-term and potentially serious or life-threatening complications. If gas continues, even with diet modification, see a healthcare provider for a checkup.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jun 26
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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