Wintergreen is a group of plants. Wintergreen once commonly referred to plants that remain green (continue photosynthesis) throughout the winter. The term evergreen is now more commonly used for this characteristic.
Wintergreen berries, from Gaultheria procumbens, are used medicinally. Native Americans brewed a tea from the leaves to alleviate rheumatic symptoms, headache, fever, sore throat and various aches and pains. During the American Revolution, wintergreen leaves were used as a substitute for tea, which was scarce.
Wintergreen is a common flavoring in American products ranging from root beer, chewing gum, mints and candies to smokeless tobacco such as dipping tobacco (American "dip" snuff) and snus. It is also a common flavoring for dental hygiene products such as mouthwash and toothpaste.
Wintergreen oil can also be used in fine art printing applications to transfer a color photocopy image or color laser print to a high-rag content art paper, such as a hot-press watercolor paper. The transfer method involves coating the source image with the wintergreen oil then placing it face-down on the target paper and pressing the pieces of paper together under pressure using a standard etching press.
Oil of wintergreen 
The Gaultheria species share the common characteristic of producing oil of wintergreen. Wintergreen oil is a pale yellow or pinkish fluid liquid that is strongly aromatic with a sweet woody odor (components: methyl salicylate (approx. 98%), a-pinene, myrcene, delta-3-carene, limonene, 3,7-guaiadiene, delta-cadinene) that gives such plants a distinctive "medicinal" smell whenever bruised. Salicylate sensitivity is a common adverse reaction to the methyl salicylate in oil of wintergreen; it can produce allergy-like symptoms or asthma.
Wintergreen essential oil is obtained by steam distillation of the leaves of the plant following maceration in warm water. Methyl salicylate, the main chemical constituent of the oil, is not present in the plant until formed by enzymatic action from a glycoside within the leaves as they are macerated in warm water. Oil of wintergreen is also manufactured from some species of birch, but these deciduous trees are not called wintergreens. Spiraea plants also contain methyl salicylate in large amounts and are used similarly to wintergreen. Although wintergreen has a strong "minty" smell and flavour, Gaultheria plants are not true mints.
Wintergreen oil is used topically (diluted) or aromatheraputically as a folk remedy for muscle and joint discomfort, arthritis, cellulite, obesity, edema, poor circulation, headache, heart disease, hypertension, rheumatism, tendinitis, cramps, inflammation, eczema, hair care, psoriasis, gout, ulcers, broken or bruised bones. The liquid salicylate dissolves into tissue and also into capillaries, so overuse is as risky as overuse of aspirin. Wintergreen also is used in some perfumery applications and as a flavoring agent for toothpaste, chewing gum and soft drinks, confectionery, in Listerine, and in mint flavorings. One surprising application is rust removal and degreasing of machinery. Wintergreen is particularly effective for breaking through sea water corrosion.
Toxicity of Wintergreen oil 
30 ml (about 1 fl oz) of oil of wintergreen is equivalent to 55.7 g of aspirin, or about 171 adult aspirin tablets (US). This conversion illustrates the potency and potential toxicity of oil of wintergreen even in small quantities.
Illiteracy may be a common factor in accidental overdoses and ingestions in adults. Treatment is identical to the other salicylates. Early use of hemodialysis in conjunction with maximal supportive measures is encouraged in any significant ingestion of methyl salicylate.
Strong warning labels are recommended for household salicylate-containing compounds such as oil of wintergreen.
See also 
- Gaultheria humifusa - alpine wintergreen
- Gaultheria ovatifolia - western teaberry or Oregon spicy wintergreen
- Chimaphila maculata - striped wintergreen
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