Salicylic acid is a monohydroxybenzoic acid, a form of phenolic acid, and a beta hydroxyl acid. The colorless crystalline organic acid is widely used in organic synthesis and functions as a plant hormone. It is derived from the salicin metabolism. It is best known for its uses as a main ingredient within tropical acne fighting products, as well as an important active metabolite of aspirin. The esters and salts of salicylic acid are known as salicylates. The inner bark serves as the medical part of the plant.
Salicylic acid has become known because of its ability to take away aches and pains and ability to reduce fevers. These medicinal properties have been used since ancient times. It is also known as being an anti-inflammatory drug. Concerning modern medicine, salicylic acid along with its derivatives are constituents of many rubefacient products. A good example is methyl salicylate being used to soothe joint and muscle pain.