For the temporary relief of: heartburn, acid indigestion, and sour stomach when accompanied with headache or body aches and pains; upset stomach with headache from overindulgence in food or drink; headache, body aches, and pain alone. Take any time - morning, noon, or night - when you need relief. Alka-Seltzer in water contains principally the antacid sodium citrate and the analgesic sodium acetylsalicylate.