Terpene Toxicity

Updated: Apr 14, 2015
  • Author: John Said Kashani, DO; Chief Editor: Asim Tarabar, MD  more...
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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. An oil derived from the Saliva officinalis tree, thujone, has recently become popular because of its hallucinogenic qualities, and it is quickly becoming a drug of abuse. [4]

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.



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 fatalities and long-term complications.

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.




United States

According to the 2009 Annual Report of the American Association of Poison Control National Poison Data System, 3362 single exposures to disinfectants containing pine oil, 10,714 single exposures to camphor, and 422 single exposures to turpentine were reported. [5] Exposure to pine oil resulted in 2 deaths, and exposure to turpentine resulted in 1 death. No deaths resulted from exposure to camphor. [5]


Morbidity and mortality [6] 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.


Males overrepresent cases associated with terpenes.


Most exposures are the result of unintentional exposures in childhood.