This section is from the "A Handbook of Useful Drugs" book, by State Medical Examining and Licensing Boards.
Oil of birch is also sold commercially as oil of wintergreen.
Properties : Pure methyl salicylate is a colorless liquid, having a characteristic, strongly aromatic, wintergreen odor and a sweetish, warm and aromatic taste. It is nearly insoluble in water, but miscible in all proportions with alcohol The oils obtained from natural sources frequently have a pinkish tint, because of the contamination with traces of iron, but in general have the same properties as methyl salicylate, to the requirements and tests for which they conform.
Action and Uses: Methyl salicylate and the oils containing it are antiseptic, and when absorbed by the skin or taken internally have the actions of salicylic acid or the salicylates (see sodium salicylate). When rubbed on the skin it is rapidly absorbed. It is frequently applied for the relief of pain in local rheumatic swellings or over inflamed nerves.
Dosage: 1 c.c. or 15 minims. When given internally this substance is preferably administered in the form of capsules, care being taken that the stomach is not empty and that plenty of water is taken. Locally, the oil may be applied pure or added to liniments.