The pharmacokinetics and pharmacodynamics pathway of salicylic acid derived from salicin, an anti-inflammatory agent produced in willow bark. It is best known for its use in anti-acne products. As a drug, it is used in the treatment of pain and inflammation and to reduce fever. Its salts and esters are known as salicylates. Genetic variations can result in changes in drug availability and can cause differences in the response of the organism to the drug.