Alka-Seltzer contains two pain relieving agents to help relieve headache. It also contains an antacid to calm an upset-stomach and buffering agents which work with aspirin to empty the stomach and aid relief.
What Alka-Seltzer XS contains: The active substances are Aspirin (Acetylsalicylic Acid) (267mg per tablet), Paracetamol (133mg per tablet), Caffeine (40mg per tablet), Sodium Hydrogen Carbonate (1723mg per tablet) and Citric Acid (954mg per tablet) Sodium content 472mg per tablet