Wintergreen is an evergreen perennial shrub in the heather family that is native to North America, with a preference for mountainous regions and moist woodlands. Native Americans used the plant to make compounds to relieve the pain of fever, headache and arthritis.
The analgesic properties of wintergreen are still harnessed in various over-the-counter topical formulas today, most notably in the muscle cream Bengay®. The active ingredient responsible for the oil's pain-relieving effects is methyl salicylate, a precursor to aspirin. This same agent, however, also presents a risk of toxicity if the oil is ingested or it is used too frequently or in large doses on the skin.