👉 Antacids are substances or medications that help to neutralize acid in the body. They work by dissolving in the stomach and breaking down food, which helps to reduce the acidity of the stomach. In simple terms, antacids are used to prevent stomach acid from damaging your teeth or bones if you swallow too much acid. Antacids can be taken before meals, after meals, or even throughout the day. They are usually prescribed by a healthcare professional and should only be taken as directed