Alka-Seltzer

Alka-Seltzer is an effervescent antacid and pain reliever owned by Bayer since 1978. It contains three active ingredients: aspirin (acetylsalicylic acid or ASA), sodium bicarbonate (also known as baking soda), and anhydrous citric acid. The aspirin is a pain reliever and anti-inflammatory, while the sodium bicarbonate is an antacid. When an Alka-Seltzer tablet is dissolved in water, the citric acid and sodium bicarbonate react to form effervescence. Alka-Seltzer was developed by head chemist Maurice Treneer and is marketed for relief of minor aches, pains, inflammation, fever, headache, heartburn, stomach ache, indigestion, acid reflux, and hangovers while neutralizing excess stomach acid. It was launched in 1931. Its sister product, Alka-Seltzer Plus, treats cold and flu symptoms. A wide variety of formulas, many using acetaminophen (paracetamol) instead of aspirin, are available under the sister brand. The product can be used in amateur chemistry lessons as an example of an endothermic reaction.