Wintergreen
Medically reviewed on August 16, 2017
Scientific Name(s): Gaultheria procumbens L. and other related species. Family: Ericaceae
Common Name(s): Wintergreen , teaberry , checkerberry , gaultheria oil , boxberry , deerberry , mountain tea , Canada tea , partridgeberry
Uses
In addition to being used as a flavoring, wintergreen and its oil have been used in topical analgesic and rubefacient preparations for the treatment of muscular and rheumatic pain. However, research reveals no clinical data regarding the use of wintergreen for any condition.
Dosing
Because of toxicity concerns, follow the suggested manufacturer's oral or topical dosage form regimen: 1 teaspoon (5 mL) of wintergreen oil is equivalent to approximately 7000 mg of salicylate or 21.5 adult aspirin tablets.
Contraindications
Oral or topical application is best avoided in children. Avoid use in patients with known hypersensitivity to any of the components in wintergreen oil. Avoid use in patients with asthma, known salicylate allergy, or GI irritation or inflammation.
Pregnancy/Lactation
Generally recognized as safe or used as food. Avoid dosages above those found in food because safety and efficacy are unproven.
Interactions
Monitor for potentiation of warfarin anticoagulation in patients using methyl salicylate or wintergreen oil.
Adverse Reactions
Wintergreen oil can induce vomiting, and in some cases, death. Counsel patients about the clinical manifestations of methyl salicylate poisoning (eg, tinnitus, acid-base disturbance, endocrine abnormalities, fluid and electrolyte imbalances, CNS toxicity).
Toxicology
When ingested, the highly concentrated liquid methyl salicylate in the form of wintergreen oil, as with other volatile oils, can induce vomiting and is a notorious source for severe, often fatal poisonings.
Botany
Wintergreen is a perennial evergreen shrub with thin, creeping stems from which leathery leaves with toothed, bristly margins arise. It is a low-growing plant native to eastern North America and usually is found in woodland and exposed mountainous areas. Its small, waxy, white or pale pink flowers bloom in late summer, developing a scarlet fruit. The aromatic leaves and fruits are edible. 1 , 2 , 3
History
American Indians reportedly used wintergreen for treating back pain, rheumatism, fever, headaches, and sore throats. 3 The plant and its oil have been used in traditional medicine as an anodyne, analgesic, carminative, astringent, and topical rubefacient.
Wintergreen oil is obtained by steam distillation of the warmed, water-macerated leaves. It is used interchangeably with sweet birch oil or methyl salicylate for flavoring foods and candies. The highest amount of methyl salicylate typically used in candy flavoring is 0.04%.
Wintergreen berries have been used to make pies. 4 A tea made from the leaves was used as a substitute for tea ( Camellia sinensis ) during the Revolutionary War. 3 The tea has been used to relieve cold symptoms and muscle aches. 5
Chemistry
Wintergreen oil contains approximately 98% to 100.5% of the methyl ester, methyl salicylate. 6 The plant has little odor or flavor until the methyl salicylate is freed. During steam distillation, the gaultherin (also described as primeveroside or monotropitoside) present in the leaves is enzymatically hydrolyzed to methyl salicylate. 1 , 7 The purified methyl salicylate is subsequently obtained through distillation. In addition, the sugars D-glucose and D-xylose are obtained. The yield of oil from the leaves is in the range of 0.5% to 0.8%. 8
Uses and Pharmacology
Small oral doses of wintergreen oil stimulate digestion and gastric secretion. 4 Topically, the oil is a counterirritant and may offer some analgesic effect because of the structural similarity of methyl salicylate to aspirin.
Animal dataResearch reveals no animal data regarding the use of willow bark.
Clinical dataResearch reveals no clinical data regarding the use of wintergreen for any condition.
Dosage
Because of toxicity concerns, follow the suggested manufacturer's oral or topical dosage form regimen: 1 teaspoon (5 mL) of wintergreen oil is equivalent to approximately 7000 mg of salicylate or 21.5 adult aspirin tablets.
Pregnancy/Lactation
Generally recognized as safe or used as food. Avoid dosages above those found in food because safety and efficacy are unproven.
Interactions
Monitor for potentiation of warfarin anticoagulation in patients using methyl salicylate or wintergreen oil. 9
Adverse Reactions
One case report documents a potential hypersensitivity reaction in a nonsmoking woman 21 years of age with a history of asthma, who complained of wheezing, dry cough, and bronchial pains after using a tartar-control toothpaste flavored with wintergreen. 10 , 11 Another case report documents a patient developing laryngeal edema after accidental ingestion of wintergreen oil. 12
Toxicology
When ingested, the highly concentrated liquid methyl salicylate in the form of wintergreen oil, as with other volatile oils, can induce vomiting and is a notorious source for severe, often fatal, poisonings. 4 , 6
Children often may associate the pleasant odor of wintergreen oil with “candy”. However, the oil may be particularly toxic to children. One teaspoon (5 mL) of wintergreen oil is equivalent to approximately 7000 mg of salicylate or 21.5 adult aspirin tablets. 12 Ingestion of as little as 4 mL in a child and 6 mL in an adult has been fatal. 6 , 13 , 14 Because of this toxicity, official labeling requirements have been changed so that no drug product may contain more than 5% methyl salicylate. 15 No deaths have been reported from ingestion of the plant itself. 1
The compound lectin has been shown to have mutagenic properties; 4 the extract is used in some insecticides. 1
The essential oil and its component can be absorbed through the skin; thus, salicylate intoxications occur following topical application of methyl salicylate or wintergreen oil. Because of the structural similarity between methyl salicylate and acetylsalicylic acid (aspirin), a toxic syndrome similar to that seen in salicylism has been observed in persons who have ingested wintergreen for prolonged periods of time. This syndrome has been characterized by tinnitus, nausea, and vomiting. 4
A man 40 years of age became suddenly and acutely ill within 1 hour after an herbalist topically applied an herbal skin cream containing an unknown amount of wintergreen oil for the treatment of psoriasis. The patient developed tinnitus followed by hyperpnea, vomiting, diaphoresis, fever, and CNS disturbance (wintergreen oil in liquid form is a highly lipid soluble). 16
An Asian woman 70 years of age, seeking relief for her chronic knee pain, developed similar clinical manifestations of methyl salicylate poisoning (eg, acid-base disturbance, endocrine abnormalities, fluid and electrolyte imbalances, CNS toxicity) after ingesting 60 mL of topical Koong Yick Hung Fa Oil (KYHFUO: contains 56.2 g of salicylic acid, the equivalent of 173 regular-strength, adult aspirin tablets) purchased at an Asian grocery store in Singapore. 17
Bibliography
1. Simon JE. Herbs: An Indexed Bibliography, 1971-1980. Hamden, CT: Shoe String Press, 1984.2. Wintergreen. The Columbia Encyclopedia , 6th ed. NY: Columbia University Press, 2003. http://www.encyclopedia.com .
3. Chevallier A. The Encyclopedia of Medicinal Plants . New York, NY: DK Publishing Inc.; 1996.
4. Duke JA, Ducellier J, Bogunschutz-Godwin MJ. Handbook of Medicinal Herbs. Boca Raton, FL: CRC Press; 1985.
5. Dobelis IN, ed. Magic and Medicine of Plants. Pleasantville, NY: Reader's Digest Association, Inc., 1986.
6. Howrie DL, Moriarty R, Breit R. Candy flavoring as a source of salicylate poisoning. Pediatrics . 1985;75:869-871.
7. Spoerke DG, Jr. Herbal Medications. Santa Barbara, CA: Woodbridge Press; 1980.
8. Leung AY. Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics. New York, NY: J. Wiley and Sons; 1980.
9. Joss JD, LeBlond RF. Potentiation of warfarin anticoagulation associated with topical methyl salicylate. Ann Pharmacother . 2000;34:729-733.
10. Toothpaste can cause allergic reaction. Nutri Health Rev . 1991;58:18.
11. McCarthy P. Asthma-flavored toothpaste. Omni . 1992;14:36.
12. Botma M, Colquhoun-Flannery W, Leighton S. Laryngeal oedema caused by accidental ingestion of Oil of Wintergreen. Int J Pediatr Otorhinolaryngol . 2001;58:229-232.
13. Tyler VE, et al. Pharmacognosy , 9th ed. Philadelphia, PA: Lea and Febiger; 1988.
14. Dreisbach RH, Robertson WO. Handbook of Poisoning , 12th ed. Norwalk, CT: Appleton and Lange; 1987.
15. Fink JL, et al, eds. Pharmacy Law Digest . St. Louis, MO: Facts and Comparisons; 1992.
16. Bell AJ, Duggin G. Acute methyl salicylate toxicity complicating herbal skin treatment for psoriasis. Emerg Med (Fremantle). 2002;14:188-190.
17. Hofman M, Diaz JE, Martella C. Oil of wintergreen overdose. Ann Emerg Med . 1998;31:793-794.
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