Flatulence

Flatulence is passing gas from the digestive system out of the back passage. It's more commonly known as "passing wind", or "farting".

Farting is often laughed about, but excessive flatulence can be embarrassing and make you feel uncomfortable around others. However, it can usually be controlled with changes to your diet and lifestyle.

Flatulence is a normal biological process and is something everyone experiences regularly. Some people pass wind only a few times a day, others a lot more, but the average is said to be about 5 to 15 times a day.

Why it happens

When you swallow food, water or saliva, you also swallow small amounts of air, which collects in the digestive system. Gases can also build up when you digest food. The body needs to get rid of the build-up by farting (flatulence) or burping (belching).

Sometimes you may not notice you have passed wind because most of the gases are odourless and often released in small quantities. Flatulence usually only has a bad smell if it contains gases that smell, such as sulphur. However, it's important to remember it's normal for the gas you pass to sometimes smell a bit.

Excessive flatulence can be caused by swallowing more air than usual or eating food that's difficult to digest. It can also be related to an underlying health problem affecting the digestive system, such as recurring indigestion or irritable bowel syndrome (IBS).

Read more about the causes of flatulence.

When to see your GP

There are no medical guidelines defining the normal frequency or volume of flatulence. You're probably the best person to assess your own symptoms.

See your GP if your flatulence is particularly troublesome – for example, if you're frequently passing smelly gas.

You should also visit your GP if you experience additional symptoms, such as:

• persistent abdominal pain and bloating
• recurring episodes of diarrhoea or constipation
• unexplained weight loss
• bowel incontinence 
• blood in your stools (faeces)
• signs of an infection, such as a high temperature, vomiting, chills, joint pain and muscle pain

These symptoms could be an indicator of a more serious health problem and may require investigation, such as a blood or stool test to look for an infection.

Controlling the problem

Excessive flatulence can usually be controlled by making changes to your diet and lifestyle, such as:

• avoiding foods known to cause flatulence
• eating smaller and more frequent meals
• eating and drinking slowly
• exercising regularly

There are also some over-the-counter medications that can help if your flatulence is troublesome, such as charcoal tablets or simethicone.

If your flatulence is related to an underlying health problem, treating the condition may help resolve it.

Read more about treating flatulence.

There are several natural causes of flatulence. Flatulence can also be caused by some health conditions related to the digestive system, or as a side effect of certain medicines.

Swallowing air

It's perfectly normal to swallow air while breathing and eating. However, it's easy to swallow a lot more air than usual without realising it. This can cause excessive flatulence.

Excess air can be swallowed by:

• chewing gum
• smoking
• sucking on pen tops or hard sweets
• having loose-fitting dentures
• not chewing food slowly and thoroughly – swallowing large pieces of food causes you to swallow more air

Hot and fizzy drinks also increase the amount of carbon dioxide in your stomach, although this is more likely to cause belching rather than flatulence.

Food and drink

Some carbohydrates in food can't be digested and absorbed by the intestines. These pass down into your colon to be broken down by bacteria, producing gas, which is released as flatulence.

Foods containing a high amount of unabsorbable carbohydrates include:

• beans
• broccoli
• cabbage
• cauliflower
• artichokes
• raisins
• pulses
• lentils
• onions
• prunes
• apples
• Brussels sprouts

Foods containing a lot of unrefined cereal fibre, such as bran, can also sometimes cause problems with wind and bloating.

Other foods and drinks that contain a sweetener called sorbitol (such as sugar-free gum or slimming products) or a type of sugar called fructose (such as fruit juice) can also cause flatulence. This means chewing sugar-free gum can cause flatulence from both the sweetener and swallowing air.

Certain foods, such as cabbage or onions, can lead to the production of gases containing sulphur, which can result in foul-smelling wind. However, the production of smelly wind can vary from person to person depending on what you eat, so it's up to you to work out which foods cause the most smell.

Health conditions

Certain health conditions can cause symptoms of flatulence, including:

• indigestion
• constipation 
• irritable bowel syndrome (IBS) – a common digestive condition, which can cause stomach cramps, bloating, diarrhoea and constipation
• coeliac disease – an intolerance to a protein called gluten, found in wheat, rye and barley
• lactose intolerance – where the body is unable to break down lactose (a natural sugar found in milk and dairy products) and can't absorb it into the blood
• gastroenteritis – a stomach and bowel infection
• malabsorption – where the intestines are unable to absorb nutrients properly
• giardiasis – an infection of the digestive system caused by tiny parasites

Medicine

Flatulence, often caused by indigestion, is a possible side effect of many types of medicine, including:

• non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen
• some laxatives
• antifungal medicines
• statins
• varenicline (Champix) – used to help people stop smoking

Excessive flatulence can usually be treated by making changes to your diet and lifestyle.

Several over-the-counter treatments are also available if your flatulence is becoming a problem.

Self care advice

Diet

You should try to avoid eating foods high in unabsorbable carbohydrates. For a list of these foods, see causes of flatulence. Certain processed foods should also be avoided as they can contain ingredients that cause flatulence, including:

• any foods with artifical sweeteners
• sugar-free sweets or chewing gum
• fizzy drinks

However, it's still important to eat a healthy balanced diet, including at least 5 portions of fruit and vegetables a day. Choose foods containing carbohydrates that are easy to digest. These include:

• potatoes
• rice
• lettuce
• bananas
• grapes
• citrus fruits, such as oranges
• yoghurt

It's important to note that people react differently to certain foods, so some foods listed above may still cause flatulence. You may find it useful to keep a food diary to see whether certain foods make your symptoms better or worse.

You may also find it useful to eat 6 small meals a day rather than 3 large ones. Smaller meals are easier to digest and may produce less gas.

There's some evidence to suggest drinking peppermint tea can help improve the symptoms of flatulence. There's also some evidence that small amounts of ginger can help with digestion or an upset stomach, which may be causing flatulence. However, pregnant women should consult their doctor before taking ginger.

Swallowing air

When eating, make sure you chew food slowly to reduce the amount of air you swallow. This will also help with digestion. Avoid chewing gum as it can also cause you to swallow more air than usual.

You should also give up smoking, if you smoke. Smoking can cause you to swallow more air than usual, and tobacco smoke can irritate your digestive system. See stop smoking for more information and advice about quitting smoking.

Exercise

Getting plenty of exercise can help improve the functioning of your digestive system and bowel. It has also been shown to help with bloating and the passage of gas.

Medications and other remedies

There are several over-the-counter remedies that can help treat the symptoms of flatulence, some of which are described below.

Charcoal tablets

Charcoal tablets are a type of medication available over the counter from pharmacists. The charcoal absorbs gas in the digestive system, which helps reduce symptoms.

Charcoal tablets may not be suitable for you if you are currently taking other medication. This is because the charcoal might absorb the medication and make it less effective. If you are taking other medication, ask your GP or pharmacist for advice before taking charcoal tablets.

Clothing containing activated charcoal, or charcoal pads placed inside clothing, can help absorb foul-smelling gas released during flatulence. These products can be purchased online.

Simethicone is another over-the-counter medication that can also sometimes help with gas problems.

Dietary supplements

Alpha-galactosidase is a dietary supplement that may help improve the digestion of carbohydrates and reduce symptoms of flatulence. It's found in a product called Beano, which has been shown to have some effect in reducing flatulence and is available from some pharmacists and health food shops.

Probiotics may also be useful in treating flatulence. Probiotics are a dietary supplement, usually sold in liquid or capsule form, which encourages the growth of "friendly bacteria" in your digestive system.

The "friendly bacteria" should help digestion and reduce the symptoms of flatulence, particularly in people with irritable bowel syndrome (IBS). Probiotic yoghurts may also help, but avoid those with artificial sweeteners or added fibre.