Tums is an antacid medication used to relieve symptoms caused by too much stomach acid, such as heartburn, sour stomach, acid indigestion, and upset stomach associated with these symptoms. It works by reducing the amount of acid in the stomach, and it belongs to a group of medications called antacids. Tums may also be used to increase calcium levels in the body, as calcium is a mineral that plays an important role in building strong bones and maintaining heart health. Tums comes in various strengths and flavor varieties. It is available in chewable tablets and is taken orally.