Terpene Toxicity

Updated: Feb 05, 2019
  • Author: John Said Kashani, DO; Chief Editor: Asim Tarabar, MD  more...
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Practice Essentials

Terpenes are natural products derived from plants that have medicinal properties and biological activity. Terpenes may be found in cleaning products, rubefacients, aromatherapy, and various topical preparations. Terpenes may exist as hydrocarbons or have oxygen-containing compounds such as ketone or aldehyde groups (terpenoids).

The basic structure of terpenes is repeating isoprene units (C5H8)n, and they are grouped according to the number of repeating isoprene units. Monoterpenes contain 2 isoprene units; examples include cantharidin, menthol, pinene, and camphor. [1]  Diterpenes contain 4 isoprene units; examples include phytol, vitamin A1  [2] , and paclitaxel (Taxol).

The best-known compounds in this group are camphor oil and turpentine. [3]  The antineoplastic agent paclitaxel is a terpene derived from yew plant bark. [4]  An oil derived from the Saliva officinalis tree, thujone, became popular because of its hallucinogenic qualities, and became a drug of abuse. [5]

Absinthe, a green liquor containing thujone, has been thought to be responsible for enhancing the creativity of many famous artists including Edouard Manet, Vincent Van Gogh, and Henri de Toulouse-Lautrec. [6]



Terpenes are local irritants and thus are capable of causing GI signs and symptoms. CNS manifestations may range from an altered mental status to seizures to coma. Aspiration is a particular concern and can result in long-term complications or fatality.

Absorption begins in the oral cavity and is rapid, as evidenced by the early onset of toxicity in significant ingestions. Terpenes are metabolized through cytochrome P450 and are excreted as conjugated metabolites by the kidney.



Most exposures are the result of an unintentional ingestion.

Some subcultures of society continue to use turpentine as an antihelminthic, purgative, and general elixir of good health. This practice may produce the potentially disastrous situation where the product is available and considered to be innocuous.

Camphorated oil often is supplied in small bottles that closely resemble castor oil. The bottles may be kept on pharmacy or grocery store shelves next to each other so that an individual with vision impairment may easily choose the incorrect preparation.

A case report described camphor toxicity in a 35-year-old Cambodian man with diarrhea, vomiting, and altered mental status. He was described as having parallel and symmetric ecchymotic streaks on his back as a result of "coining". In this case, toxicity occurred by the application of camphor to the skin prior to coining. Toxicity occurred presumably by transcutaneous absorption. [7]



According to the 2017 Annual Report of the American Association of Poison Control National Poison Data System, 3251 single exposures to disinfectants containing pine oil, 9975 single exposures to camphor, and 290 single exposures to turpentine were reported. No deaths were reported for any of the above exposures. [8]

Males overrepresent cases associated with terpenes. Most exposures are in children and are unintentional.



Morbidity and mortality [9]  associated with exposure to terpenes is largely related to the degree of CNS depression and if aspiration occurs. Despite the toxicity of these agents, morbidity is extremely low. Mortality is rare. Most patients make full recoveries without sequelae. Aspiration of hydrocarbons may result in serious complications requiring long-term follow-up.


Patient Education

Preventive education is essential. Information regarding proper storage of chemicals is important.

All families of victims should be given the telephone number of the local or regional poison control center.