Why do indigestion remedies sometimes make you burp?

Many indigestion remedies, particularly antacids, work by neutralising stomach acid. When antacids come into contact with stomach acid, they produce carbon dioxide gas as a byproduct of the neutralisation reaction. This gas can cause you to burp, which can help relieve the feeling of indigestion.

Also, some indigestion remedies contain ingredients that can directly stimulate the production of gas in the stomach. For example, sodium bicarbonate (baking soda) is a common ingredient in antacids and it can react with stomach acid to produce carbon dioxide gas.

Finally, some indigestion remedies can relax the muscles in the oesophageal sphincter, which is the valve that connects the stomach to the oesophagus. This relaxation can allow gas and stomach contents to flow back into the oesophagus, causing a burp.