Wintergreen oil is a compound that can be distilled from the twigs of wintergreen or any of a number of related shrubs from around North America. It can also be made artificially from a combination of methanol and salicylic acid. This is the most common production method for modern commercial use.
Although pure wintergreen oil should not be ingested internally because the chemical compounds are toxic even at lower doses, wintergreen oil is safely used as a flavoring in some types of food products as well as a fragrance. It is also used topically in some cases.
In food or drinks, wintergreen is most commonly used as a flavoring for candy and chewing gum in low concentrations. It is generally used on its own due to the strength of the flavor. It is commonly used as a pharmaceutical flavoring and in products like toothpaste and mouthwash, where it is also an antiseptic aid.
As a toxic agent, wintergreen oil is sometimes used as an antiseptic, although effectiveness for this function has not been clinically proven. There are a number of unproven claims that topical usage of the oil can promote smoother digestion.
Wintergreen oil is sometimes used for muscle pain and headaches. Some of the therapeutic effect described comes from counter-irritation that affects the original inflammation. However, there is also evidence that when absorbed through the skin, wintergreen oil is broken up into components that include NSAIDs, or analgesic compounds.
Even when used topically, wintergreen oil can accumulate to toxic levels when absorbed through the skin. Because of this, it is best used heavily diluted and not as a regular treatment regimen.
The most unusual characteristic of hard candies containing wintergreen oil is their tendency to form a spark when crushed. The bonds that form between the dried oil and sugar release electricity when broken, enough to be visible in a dark room.