What happens in my body when i burp?

Eat and drink

With every mouthful of food or drink, you swallow a couple of millilitres of air – mostly nitrogen and oxygen. Carbonated drinks also add another millilitre or so of carbon dioxide.

Gases separate

The gases separate from the food in your stomach and press against the lower oesophageal sphincter, which holds the top of the stomach closed.

Sphincter opens

Eventually, the pressure forces the sphincter open and the air rushes out. The belching sound is caused by vibrations in the sphincter and oesophagus wall

Read more:

• What happens in my body when I feel hungry?
• What happens in my body when I sneeze?

Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun facts.