Maximum Strength Pepcid AC Heartburn Relief Tablets with famotidine provide fast-acting prevention and relief of heartburn associated with acid indigestion and sour stomach. Each acid controlling tablet contains 20 mg of famotidine, a known acid reducer that helps relieve heartburn brought on by eating or drinking certain food and beverages. Keep a package in your bag or at your desk for easy-access to treat heartburn on-the-go. You can take Maximum Strength Pepcid AC as little as 10 minutes before eating, and know you have strength on your side all day or all night.***Prevents heartburn if taken 10 to 60 minutes before a meal.**Based on 9-hour acid control studies during the day and 12-hour acid control studies during the night. Acid control does not imply symptom relief.