Alka-Seltzer Original Effervescent Heartburn Relief and Pain Relief Antacid Tablets bring fast relief of heartburn, upset stomach, and acid indigestion with headache or body aches—allowing you the freedom to enjoy your favorite foods and activities. Providing trusted and effective relief for more than 80 years, these Alka-Seltzer tablets contain anhydrous citric acid and sodium bicarbonate that neutralize acid in seconds. Unlike other antacids, Alka-Seltzer Original contains aspirin, which acts as an analgesic to alleviate pain accompanied by acid indigestion. These effervescent antacid tablets dissolve quickly in water to deliver fast relief that you can hear, see, and feel working.