Primary Health Maximum Strength acid Reducer Famotidine 20mg Tablets, 100 Count, prevents and relieves heartburn caused by acid indigestion and sour stomach brought on by eating and drinking certain foods and beverages, such as rich, spicy, fatty or fried foods, Chocolate, caffeine, alcohol, and certain fruits and vegetables. The active ingredient Famotidine belongs to the H2 blockers class of drugs, and relieves symptoms by decreasing the amount of acid your stomach makes. For ages 12 and older.