What is Flatulence?

Flatulence is the passing of gas from the bowel through the anus, often called passing wind or farting. It is a normal body function. Most healthy adults pass gas about 10 to 20 times a day, usually without noticing.

Where the gas comes from

• Swallowed air. We swallow small amounts of air while eating, drinking, talking or chewing gum.
• Gut bacteria. Bacteria in the large intestine ferment food that was not fully digested, such as some fibres and sugars, and release gas.

The gas is mainly nitrogen, carbon dioxide, hydrogen and sometimes methane. The smell comes from a small amount of sulphur-containing gases.

When it becomes a problem

Flatulence is a concern when it is much more frequent than usual, painful, very embarrassing, or comes with other symptoms such as bloating, cramps, diarrhoea or weight loss. It can then point to a food intolerance or a digestive condition.

Key points

• Passing gas is normal and healthy.
• Diet, eating habits, constipation and certain conditions can increase it.
• Most cases improve with simple changes in food and habits.
• Blood in the stool, black stools, unexplained weight loss, persistent vomiting, severe pain or fever need a doctor's assessment.