For fast effervescent relief of acid indigestion, upset stomach and heartburn, turn to Alka-Seltzer® Gold. It's safe for sensitive stomachs and it does not contain aspirin. Ingredients Active Ingredients (in each Tablet) - Purpose: Anhydrous Citric Acid 1000 mg - Antacid. Potassium Bicarbonate 344 mg - Antacid. Sodium bicarbonate (heat-treated) 1050 mg - Antacid. Inactive Ingredients: Magnesium Stearate, Mannitol.