Methyl salicylate (chemical formula C6H4(HO)COOCH3; also known as oil of wintergreen, betula oil, methyl ester) is a natural product of many species of plants. Some of the plants producing it are called wintergreens, whence the common name.
Methyl salicylate is toxic if taken internally in large amounts, and plants containing it probably evolved it as an anti-herbivory defence. Numerous plants produce methyl salicylate in very small amounts. Plants producing it in significant amounts (readily detected by scent) include:
Structurally, it is methylated salicylic acid. Commercial methyl salicylate is now synthesized from salicylic acid, but in the past, it was commonly distilled from the twigs of Sweet Birch (Betula lenta) and Eastern Teaberry (Gaultheria procumbens).
It is used as an ingredient in deep heating rubs, and in small amounts as a flavouring agent. It also has the property of fluorescence, converting ultraviolet light into visible blue light.