Alka-Seltzer's chemical formula is C16H17NaO14. This chemical compound is also known as 2-acetoxybenzoic acid, hydrogen carbonate, sodium and citric acid.
An Alka-Seltzer tablet contains citric acid, aspirin and sodium hydrogen carbonate. Aspirin, which is a NSAID or non-steroidal anti-inflammatory drug, blocks cyclo-oxygenase in the body. Cyclo-oxygenase produces prostaglandin, which can cause swelling or pain. So, taking aspirin gets rid of inflammation or pain in the body, according to Netdoctor. Both sodium hydrogen carbonate and citric acid reduce the acidity of the stomach's juices. This aids in relieving indigestion and heartburn and thus in settling the stomach. Alka-Seltzer is recommended for relieving headaches that are associated with an upset stomach This tablet can also be taken for relieving pain related to sore throat, toothache and menstruation.