Terpene Toxicity

Updated: Apr 29, 2023
  • 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 terpene compounds are camphor oil and turpentine. [3] The antineoplastic agent paclitaxel is a terpene derived from yew plant bark. [4] The terpene thujone is found in a variety of plants, including arborvitae (Thuja), sage (Salvia officinalis ), and wormood (Artemisia absinthium). Diviner's sage (Salvia divinorum), which contains the hallucinogenic terpene salvinorin A, was originally used in shamanic ceremonies of the Mazatec Indians of Mexico but became popular internationally as a recreational drug, with attendant adverse effects. [5]

Absinthe is a liquor whose ingredients include the flowers and leaves of wormwood, which provide thujone and help give absinthe its green color. Absinthe was very popular in France from the 19th to the early 20th century, and it 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] Absinthe also gained a reputation as a dangerously addictive psychoactive drug, and was banned in many countries for most of the 20th century. [7]   However, chemical analysis of absinthe samples from the early 1900s found that thujone levels were so low that psychoactive effects from it were unlikely. [8]



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 terpene 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.

Exposure to topical products that contain camphor can cause serious toxicity in young chlidren. [9] 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. [10]



According to the 2021 Annual Report of the American Association of Poison Control National Poison Data System, 3710 single exposures to disinfectants containing pine oil, 7572 single exposures to camphor, and 197 single exposures to turpentine were reported. Two deaths were reported among all of the above exposures. [11]

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



Morbidity and mortality [12]  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.