Antacids are medicines that counteract (neutralise) the acid in your stomach to relieve indigestion and heartburn. They come as a liquid or chewable tablets and can be bought from pharmacies and shops without a prescription.
The substances which neutralize the acids of the stomach are called antacids. Acidity in the stomach causes the sensation of heartburn, antacids are taken to relieve this sensation. They are taken orally to suppress the effects of acidity.