Other Information: Each tablet contains: sodium 567 mg. Store at room temperature. Avoid excessive heat. Alka-Seltzer in water contains principally the antacid sodium citrate and the analgesic sodium acetylsalicylate. Misc: Anhydrous Citric Acid/Antacid. Aspirin (NSAID)/Analgesic. Sodium Bicarbonate/Antacid. Fast relief of: heartburn; upset stomach; acid indigestion; with headache; body aches. Take Alka-Seltzer any time - morning, noon, or night - when you need relief from heartburn, upset stomach, acid indigestion with headache or body aches. Questions or comments? 1-800-986-0369 (Mon - Fri 9 am - 5 pm EST).