Compound Monograph
Salicylic Acid
Salicylic acid is a phenolic acid found in many plants and the active metabolite of willow-bark salicylates and aspirin.
Classification
Salicylic Acid is a phenolic acid (salicylate), part of the phenolics class. Antioxidant compounds built around one or more phenol rings — the flavonoids, tannins, phenolic acids, coumarins, and pigments behind much of a plant's protective chemistry.
Where Does It Come From? (9)
Salicylic Acid is a naturally occurring phenolic acid (salicylate), found in Willow, Meadowsweet, Jasmine and 6 other sources. It is flagged as moderately toxic.
Research & Evidence
Salicylic acid is a simple phenolic acid that occurs naturally in willow, meadowsweet and many other plants, and that is produced in the body from salicin and from aspirin (acetylsalicylic acid). It has anti-inflammatory properties and, applied to the skin, is keratolytic—loosening the outer layer of skin—which is why it is widely used in topical treatments for acne, warts and dandruff. It also functions as a plant hormone involved in defence signalling.
Toxicity & Safety
Topically, salicylic acid is well established but can irritate skin, and extensive application can lead to systemic absorption. Taken internally in larger amounts it is more irritating to the stomach than its acetylated relative aspirin, and high doses can cause salicylate toxicity (ringing in the ears, nausea, acid-base disturbances). It carries the general salicylate cautions, including avoidance by those allergic to aspirin and the theoretical Reye’s syndrome risk in children with viral illness.