Flatulence (Gas)

Reviewed on 7/22/2022

What to Know About Flatulence (Gas), Excessive and Chronic

Symptoms of excessive gas include bloating, abdominal pain, belching, and increased frequency of passing gas.
Symptoms of excessive gas include bloating, abdominal pain, belching, and increased frequency of passing gas.
  • Flatulence or intestinal gas is the state of having excessive stomach and/or intestinal gas (waste gas produced during digestion) that is usually released from the anus with sound and/or odor.
  • Causes of excess gas in the digestive tract include:
    • swallowed air,
    • breakdown of undigested foods,
    • lactase intolerance, and
    • malabsorption of certain foods.
  • Much of the gas generated is due to the microbial breakdown of foods so that gases, for example, hydrogen, carbon dioxide, and methane are generated; the odor is from other trace waste gases or compounds such as skatole and sulfur-containing substances.
  • Symptoms of excessive gas or flatulence may include:
    • increased frequency or excessive instances of passing gas,
    • smelly or foul-smelling gas production (flatulence),
    • belching,
    • abdominal, bloating, and/or
    • abdominal pain or discomfort.
  • Excessive gas or flatulence usually is not a medical emergency; however medical care should be sought quickly if a person develops other symptoms such as:
  • Diagnosis of excessive or chronic gas usually is done by a healthcare professional after reviewing the patient's history and physical exam. In most instances, tests are not run but if needed, analysis of patients' breath and flatus (gas passed out of the rectum) may be ordered.
  • Other rarer causes of excessive flatulence or gas may require additional tests such as colonoscopy, X-rays, and/or CT scans.
  • Natural and home remedies for excessive gas or flatulence include dietary changes since chronic flatulence is often caused by certain foods that can be eliminated from the diet.
  • Medical treatment for excessive flatulence may include antibiotic treatment, increased dietary fiber intake, and including probiotics in the diet (recommended by some, but not all healthcare professionals). More serious causes of excessive flatulence (for example, irritable bowel syndrome [IBS] and small intestinal bacterial overgrowth [SIBO]) may require additional medication and testing.
  • Over-the-counter (OTC) medications to treat excessive flatulence include compounds such as Beano (an OTC that contains sugar and digestive enzyme), antacids, and activated charcoal.
  • Excessive flatulence can be reduced or prevented with several methods such as:
    • modifying your eating habits,
    • changing your diet to avoid those foods that cause you personally to produce excessive gas,
    • utilizing over-the-counter anti-gas compounds, and
    • avoiding dairy products if you are lactose intolerant.
  • Most individuals that alter their diet can reduce or prevent excessive flatulence and thus have a good prognosis.

What Is Flatulence or Intestinal Gas?

The definition of flatulence is gas (generated during digestion or waste gases), usually in excess, that is present in the intestinal tract and usually removed from the body by passing out through the anus, often accompanied by sound and odor when the gas is expelled by the body. Common terms for flatulence include terms such as farts, breaking wind, and passing gas. Some individuals include belching (passing gases from the stomach through the mouth) under flatulence.

  • The primary components of gas (known as flatus, pronounced FLAY-tuss) are 5 odorless gases: nitrogen, hydrogen, carbon dioxide, methane, and oxygen.
  • The characteristic smelly odor is attributed to trace gases such as skatole, indole, and sulfur-containing compounds.
  • The flammable character of flatus is caused by hydrogen and methane. The proportions of these gases depend largely on the bacteria that live in the human colon that digest, or ferment, food that has not been absorbed by the gastrointestinal (GI) tract before reaching the colon.
  • An estimated 30-150 grams of this undigested food reach the colon in the form of carbohydrates every day. But this amount can vary with diet and how well the GI tract is functioning.

A condition termed "vaginal flatulence" is the release of air trapped in the vagina during or after sexual intercourse that sounds like flatulence when expelled from the vagina, but does not contain waste gases and has no specific odor. It is not flatulence, but termed so because of the sound emitted when the air escapes the vagina.

How Much Flatulence or Gas Does a Person Pass Per Day?

Most people produce about 1-3 pints of gas a day and pass gas about 14 times a day. Flatulence itself, although not life-threatening, can definitely cause social embarrassment. This embarrassment is often the reason why people might seek medical help for excessive gas.

What Is Excessive Flatulence or Intestinal Gas?

Excessive gas or flatulence is defined by some researchers as passing gas more than 20 times per day. Increased flatulence occurs when a person passes gas more than about 14 times a day and extreme flatulence is ill-defined but occasionally used to describe excessive and/or constant passing of gas and is occasionally related to excessively smelly gas production.

Chronic flatulence is also not well defined but is used to describe excessive flatulence that may occur daily over weeks to years.

What Causes Excessive Flatulence or Gas?

Excess gas in the digestive tract (esophagus, stomach, small intestine, and colon/large intestine) can come from two sources: 1) increased intake of gas, for example, from air swallowed; or 2) increased production of gas as certain undigested foods are broken down by harmless bacteria normally found in the colon. Undigested foods may also occur in chronic intestinal problems such as chronic megacolon, patients undergoing chemotherapy or in certain infectious diseases such as giardiasis.

Swallowed air

Swallowed air (aerophagia) can occur with improper swallowing while eating or even unconscious swallowing of air out of habit.

  • Activities that cause a person to swallow air include rapid drinking, chewing gum, use of tobacco products, sucking on hard candy, drinking carbonated beverages, loose dentures, and hyperventilation
  • Most people burp or belch to expel this excess swallowed air. The remaining gas moves into the small intestine. The air moves along to the large intestine for release through the rectum.
  • Analysis of the gas can help determine if it originated from aerophagia (mostly nitrogen, also oxygen, and carbon dioxide) or GI production (mainly carbon monoxide, hydrogen, and methane).

Lactase intolerance

Another major source of flatulence is lactose intolerance, which results in a decreased ability to digest lactose, a natural sugar found in milk and other dairy products such as cheese and ice cream, and in certain processed food such as bread, cereal, and salad dressing. This flatulence is often associated with diarrhea and cramping but can appear as only gas.

Many people normally have low levels of the enzyme lactase needed to digest lactose after childhood. Also, as people age, their enzyme levels decrease. As a result, over time people may experience increasing amounts of gas after eating food containing lactose and develop chronic flatulence with gas pain(s). One way to remedy gas pain or get gas pain relief is to avoid foods that contain lactose.

What Causes Symptoms of Excessive Flatulence or Gas?

Signs and symptoms of excessive flatulence are increased passage of gas, abdominal bloating or pain, and belching. Embarrassment can be caused by the increased passage of flatus or the often-offensive odor it causes.

  • Gas: Everyone passes gas (flatulate) normally each day. A certain amount of gas is present in the GI tract at any one time, mainly in the stomach and colon. The average person passes gas about 10 times each day and up to 20-25 times is considered normal. More than that may be excessive.
  • Belching: An occasional belch during or after meals is normal and releases gas when the stomach is full of food. But if a person belches frequently, he or she may be swallowing too much air and releasing it before the air enters the stomach. Some people swallow air to make themselves belch, thinking it will relieve their discomfort. This practice may turn into an annoying habit. Belching may signal a more serious upper GI disorder such as peptic ulcer disease, gastroesophageal reflux disease (GERD), or gastroparesis.
  • Abdominal bloating: Many people believe that too much gas causes abdominal bloating. However, people who complain of bloating from gas often have normal amounts of gas. They actually may be unusually aware of gas in the digestive tract. A diet of fatty foods may delay stomach emptying and cause bloating and discomfort, but not necessarily too much gas. Certain conditions may cause bloating, such as irritable bowel syndrome, Crohn's disease, or colon cancer. People with scar tissue (adhesions) from abdominal operations or internal hernias may have a sensation of bloating because of increased sensitivity to gas.
  • Abdominal pain and discomfort: Some people have pain when gas is present in the intestine. When pain is on the left side of the colon, it can be confused with heart disease. When the pain is on the right side of the colon, it may mimic gallstones or appendicitis.

What Are Other Causes of Excessive Flatulence or Gas?

Certain conditions can result in other foods being poorly absorbed in the gastrointestinal (GI) tract, allowing for increased bacterial activity.

  • Malabsorption syndromes: Malabsorption syndromes can be the result of decreased production of enzymes by the pancreas or problems with the gallbladder or lining of the intestines.
  • SIBO (small intestinal bacterial overgrowth): SIBO is a condition in which there is an increase in the number and/or alteration of the bacterial types in the upper gastrointestinal tract that may result in bloating, flatulence, abdominal and/or gas pain discomfort, and diarrhea. The syndrome is usually associated with small intestinal motility disorders and is treated with antibiotics.
  • Bowel function: If transit through the colon is slowed down for any reason, bacteria have an increased opportunity to ferment the remaining material. If a person is constipated or has decreased bowel function for any reason, flatulence can develop.
  • Changes in bowel habits: Changes in bowel habits can be a result of the following:

What Types of Foods Can Cause Excessive Gas and/or Gas Pain?

If the body does not digest and absorb some carbohydrates (for example, the sugar, starches, and fiber found in many foods) in the small intestine because of a shortage or absence of certain enzymes there, this undigested food then passes from the small intestine into the large intestine, where normal, harmless bacteria break down the food, producing hydrogen, carbon dioxide, and, in about a third of all people, methane. Eventually, these gases exit through the rectum.

Foods that produce gas in one person may not cause gas in another. Some common bacteria in the large intestine can destroy the hydrogen that other bacteria produce. The balance of the two types of bacteria may explain why some people have more gas than others.

Foods that may cause acute and/or chronic constant flatulence or gas include:

  • Most foods that contain carbohydrates can cause gas. By contrast, fats and proteins cause little gas. These common foods and their natural components may create gas:
    • Raffinose: Beans contain large amounts of the complex sugar known as raffinose. Smaller amounts are found in cabbage, Brussels sprouts, broccoli, asparagus, and in other vegetables and whole grains.
    • Starches: Most starches (potatoes, corn, noodles, and wheat) produce gas as they are broken down in the large intestine. Rice is the only starch that does not cause gas.
    • Fructose: The sugar known as fructose occurs naturally in onions, artichokes, pears, and wheat. It is also used as a sweetener in some soft drinks and fruit drinks.
    • Dark beer and red wine
    • Sorbitol: This sugar is found naturally in fruits including apples, pears, peaches, and prunes. It's also used as an artificial sweetener in sugar-free gum, candy, and other diet products.
    • Fiber: Many foods contain soluble and insoluble fiber. Soluble fiber dissolves easily in water and takes on a soft, gel-like texture in the intestines. Found in oat bran, beans, peas, and most fruits, soluble fiber is not broken down until it reaches the large intestine, where digestion causes gas. Insoluble fiber, on the other hand, passes essentially unchanged through the intestines and produces little gas. Wheat bran and some vegetables contain this kind of fiber.

25 Foods and Drinks Can Cause Excessive Flatulence and Gas?

The following is a list of foods, drinks and other items that may be associated with chronic, constant, extreme, and/or increased flatulence and/or gas pains in certain individuals:

  1. Milk and other dairy products
  2. Beans
  3. Sodas
  4. Hard candy
  5. Lentils
  6. Wheat
  7. Potatoes
  8. Pasta
  9. Oat bran
  10. Apples
  11. Peaches
  12. Pears
  13. Bananas
  14. Apricots
  15. Melons
  16. Prunes
  17. Raisins
  18. Broccoli
  19. Brussels sprouts
  20. Cauliflower
  21. Corn
  22. Peas
  23. Onions
  24. Shallots
  25. Chewing gum

What Foods Reduce Flatulence or Gas?

Although there is little data to support the claim that many foods can reduce gas, the following is a partial list of those foods that are listed by dietitians and others that are considered to reduce flatulence:

  • Probiotics
  • Yogurt
  • Ginger
  • Raw honey (not for infants and children under the age of 1)
  • Peppermint
  • Water
  • Cinnamon
  • Juices made from kale, spinach, cucumbers, and other greens
  • Pineapple
  • Flaxseed
  • Fennel

When to Seek Medical Care for Excessive Flatulence or Gas

Seek medical attention whenever symptoms other than simply excess flatulence occur such as:

  • Gas pain(s)
  • Severe crampy abdominal discomfort
  • Change in bowel habits
  • Diarrhea
  • Constipation
  • Blood in the stool
  • Fever
  • Nausea
  • Vomiting
  • Abdominal pain and swelling, particularly in the right lower part of the abdomen
  • Chronic flatulence

Which Specialties of Doctors Treats Excessive Flatulence or Gas?

Although the person's primary care doctor may treat some people with flatulence, with chronic and extreme flatulence problems, usually a gastroenterologist is consulted.

Depending upon the underlying problem, other consultants such as infectious disease specialists, endocrinologists, and possibly immunologists may be involved in both diagnosis and treatment. Depending upon the underlying cause, (for example, achlorhydria, diverticula), other specialists such as internal medicine and even a surgeon may be consulted.

How Is the Cause of Excessive Flatulence or Gas Diagnosed?

A healthcare professional may review what the patient eats and the symptoms produced. The patient might be instructed to keep a food and drink diary for a specific period of time and track the passage of gas during the day. A careful review of diet and the amount of gas passed may help relate specific foods to symptoms and determine the severity of the problem.

The primary tests, if necessary, will likely include measuring the amount of hydrogen in the patient's breath after the person eats suspected foods. Because bacteria are largely responsible for the production of hydrogen, an increase in exhaled hydrogen as measured by the breath test will suggest food intolerance, with the bacteria fermenting the undigested food to produce excess gas. After the patient eats a problem food, breath testing should show an increase in hydrogen in as little as 2 hours.

Another possible test is an analysis of flatus for gas content. This should help differentiate gas produced by swallowing air from gas produced in the gastrointestinal (GI) tract.

If these tests produce no diagnosis, broader testing can be accomplished to help exclude more serious disorders such as diabetes, cancer, malabsorption, cirrhosis of the liver, poor thyroid function, and infection.

If a patient has abdominal pain or appears to have a swollen abdomen, the healthcare professional may have X-rays taken to show intestinal obstruction or perforation. X-rays can also be taken after the patient drinks X-ray dye to show the GI tract, which can be followed up with an internal view of the colon through colonoscopy if problems are noted.

If lactase deficiency is the suspected cause of gas, the healthcare professional may suggest the patient avoid milk products for a period of time. A blood or breath test may be used to diagnose lactose intolerance.

What Natural or Home Remedies Help Relieve Excessive Flatulence or Gas?

Flatulence is most often related to diet, and sometimes to those habits that cause a person to swallow air. One home remedy is to begin to try to remove problem foods from the diet. For many people, this is a trial-and-error procedure on how to relieve and/or prevent excessive gas or flatulence.

  • Keep a food diary: This may take careful observation to notice what foods cause increased gas. Keep a food diary and note the excess passage of gas. Any of the gas-producing foods can be removed from the diet one group at a time until the person experiences relief. Sorbitol and fructose are common offenders, so as a remedy try removing these foods first.
  • Elimination diet: If this method does not work, a more restrictive approach is to start with a very limited number of safe foods and add one new food every 48 hours in order to determine what food or food group causes difficulty. If the offending food is found, then the affected person can avoid eating that food or be prepared for its consequences.
  • Avoid lactose: If lactose intolerance is suspected to cause the problem, remove all dairy foods from the diet for 10-14 days to assess the effect on flatulence (using a diary). The enzyme lactase, which aids with lactose digestion, is available in liquid and tablet form without a prescription (Lactaid, Lactase, Dairy Ease). Adding a few drops of liquid lactase to milk before drinking it or chewing lactase tablets just before eating helps digest foods that contain lactose. Also, lactose-reduced milk and other products are available at many grocery stores (Lactaid, Dairy Ease).
  • Undergarments: If odor is a concern, there is also some reported success with charcoal filter undergarments.
  • Avoid swallowing air: If belching is a problem, avoid the behaviors that cause the affected person to swallow air, such as chewing gum or eating hard candy. Eat slowly. Make sure dentures fit properly.
  • Avoid overeating: In general, avoid overeating because this contributes to flatulence as well as obesity. Limit high-fat foods to reduce bloating and discomfort. The stomach will empty faster, allowing gases to move into the small intestine.

Natural and home remedies may or may not cure or eliminate chronic, increased, constant or extreme flatulence (gas). In some people, home remedies may help reduce symptoms. Individuals are encouraged to discuss home remedies and gas symptoms with their health-care professional.

What Is the Treatment for Excessive Flatulence or Gas?

The goal of the treatment of flatulence is to reduce gas and smelly odor. Medical intervention includes treatment with antibiotics if bacterial overgrowth of the GI tract is suspected or evidence of parasitic infection is seen.

  • Some promising studies have investigated feeding nonoffensive strains of bacteria (using probiotics) to push out the bacteria that are offensive, although no established treatments are available at this time.
  • Regulation of bowel function is essential. Constipation should be treated with increased dietary fiber or certain laxatives.
  • In cases where anxiety causes the person to swallow air, the doctor may suggest the person seek mental health counseling to change habit patterns.

What OTC or Prescription Medicine Treat Excessive Flatulence or Gas?

If the person does not want to avoid the foods that cause gas, many nonprescription over-the-counter (OTC) medicines are available to help reduce symptoms.

  • Beano is an enzyme supplement that may be useful with bean ingestion. It contains the sugar-digesting enzyme that the body lacks to digest the sugar in beans and many vegetables. Beano has no effect on gas caused by lactose or fiber. Beano can be purchased over-the-counter. Add 3-10 drops per serving just before eating beans and vegetables to break down the gas-producing sugars during digestion.
  • Antacids, such as Mylanta II, Maalox II, and Di-Gel, contain simethicone (also termed an anti-gas pill or gas pill), a foaming agent that joins gas bubbles in the stomach so that gas is more easily belched away. However, these medicines have no effect on intestinal gas. These can be taken before meals. Dosage varies.
  • Activated charcoal tablets (Charcocaps) may provide relief from gas in the colon. Gas can be reduced if tablets are taken before and after a meal. The usual dose is 2-4 tablets taken just before eating and one hour after meals.
  • Certain prescription medicines may help reduce symptoms, especially if you have a disorder such as irritable bowel syndrome. Some medicines such as metoclopramide (Reglan) have also been shown to decrease gas complaints by increasing gut activity.

Is It Possible to Prevent Excessive Flatulence or Gas?

  • Elimination diet: The reduction or prevention (cure) of increased flatulence is often best accomplished by understanding what foods cause you personally to produce excess gas. This can be done by starting off with a simple diet and slowly adding one food at a time to determine which foods cause you to produce gas. If you get excessive or increased flatulence after eating a particular type of food, you have likely identified how to eliminate gas by eliminating that food from your diet. Once these foods are identified, they can be avoided resulting in less gas production.
  • Chew slowly: Taking the time to chew your food and swallow it without introducing air and avoiding carbonated drinks may also reduce flatulence and/or burping.
  • Medications: Some individuals can reduce or prevent excess gas formation by using OTC products like Beano which will help digest sugars found in beans. Other nonprescription products such as simethicone can help reduce gas formation.
  • Lactose: For those individuals who are lactose intolerant, lactase may be taken before eating or drinking dairy products may help reduce gas; some healthcare professionals recommend simply trying to avoid dairy products in general. There are some lactose free products available such as milk, cottage cheese, sour cream, yogurt, and ice cream, and some are sold under the names "Lactaid," or "Green Valley."
  • Underwear: In addition, some individuals have invented underwear with charcoal embedded in the clothing and claim it is effective in reducing smelly flatulence.

What Is the Prognosis for a Person With Excessive Flatulence or Gas?

The majority of individuals with flatulence have a good to excellent prognosis if they simply change their dietary habits and occasionally use OTC anti-gas medications. People with more serious causes of flatulence have a fair prognosis as they may require additional treatments to reduce or eliminate the underlying cause.

Is SIBO Causing You Excessive Flatulence?

Small intestinal bacterial overgrowth (SIBO) occurs when bacteria that resembles the bacteria normally found in the colon proliferate in large numbers in the small intestine. Symptoms of SIBO include

  • excess gas (flatus),
  • diarrhea,
  • abdominal bloating and/or distension, and
  • abdominal pain.

The symptoms of SIBO tend to be chronic. A typical person with SIBO may have symptoms that fluctuate in intensity over months, years, or even decades before the proper diagnosis is made.

Reviewed on 7/22/2022
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Grace, E., et al. "Small Intestinal Bacterial Overgrowth." Aliment Pharmacol Ther. 2013;38(7):674-688.

Johnson, D.A. "Belching, Bloating, and Flatus: Helping the Patient Who Has Intestinal Gas." Medscape. Oct. 7, 2010. <https://www.medscape.com/viewarticle/729672>.