Antacid is a medicine that reduces acid in the stomach. This medicine relieves indigestion (general term for pain or discomfort felt in the stomach), heartburn (when acid moves up from the stomach into the gullet and causes a burning pain behind your breastbone), stomach ulcer (open sores that develop on the lining of the stomach) and gastritis (inflammation of the stomach lining).
Antacids are typically safe for most people.