Eat and drink
![What happens in my body when i burp? © Peter Sucheski What happens in my body when i burp? © Peter Sucheski](https://c02.purpledshub.com/uploads/sites/41/2018/11/burp-1-5ef0c85.jpg?webp=1&w=1200)
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
![What happens in my body when i burp? © Peter Sucheski What happens in my body when i burp? © Peter Sucheski](https://c02.purpledshub.com/uploads/sites/41/2018/11/burp-2-8780b4e.jpg?webp=1&w=1200)
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
![What happens in my body when i burp? © Peter Sucheski What happens in my body when i burp? © Peter Sucheski](https://c02.purpledshub.com/uploads/sites/41/2018/11/burp-3-b3a1de0.jpg?webp=1&w=1200)
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
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