Wintergreen oil is a natural essential oil extracted from the leaves of the Gaultheria procumbens plant, which is also known as the eastern teaberry, checkerberry, or wintergreen. The oil is commonly used in aromatherapy, as well as in various medicinal and cosmetic applications. The main active ingredient in wintergreen oil is methyl salicylate, which is a compound that is commonly found in over-the-counter pain relief products. Methyl salicylate has anti-inflammatory, analgesic, and antipyretic properties, which make wintergreen oil a popular natural remedy for pain relief.