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IUPAC name N,N'-Diethyl-3-methylbenzamide
Other names N,N'-Diethyl-m-toluamide
CAS number 134-62-3
Molecular formula C12H17NO
Molar mass 191.27 g/mol
Density 0.998 g/mL
Melting point

-45 °C

Boiling point

288-292 °C

Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

N,N-diethyl-m-toluamide, abbreviated DEET, is an insect repellent chemical. It is intended to be applied to the skin or to clothing, and is primarily used to protect against insect bites. In particular, DEET protects against tick bites (which transmit Lyme disease, several rickettsioses, tick-borne meningoencephalitis and other tick-borne diseases) and mosquito bites (which transmit dengue fever, West Nile virus, Eastern Equine Encephalitis (EEE), and malaria).

DEET is believed to work by blocking insect receptors (notably those which detect carbon dioxide and lactic acid) which are used to locate hosts. DEET effectively "blinds" the insect's senses so that the biting/feeding instinct is not triggered by humans or animals which produce these chemicals.



DEET was developed by the United States Army, following its experience of jungle warfare during World War II. It entered military use in 1946 and civilian use in 1957. Originally tested as a pesticide on farm fields, the US Government applied it for war time usage, particularly when in Vietnam and around that region of Asia.


A slightly yellow liquid at room temperature, it can be prepared from m-methylbenzoic acid and diethylamine. This can be achieved by preparing the acid chloride and subsequently reacting that with the diethylamine. It can be distilled under vacuum: b.p. 111°C at 1 mm Hg. It is considered a mild irritant.


  DEET is often sold and used in concentrations up to 100%. Consumer Reports found a direct correlation between DEET concentration and hours of protection against insect bites. 100% DEET was found to offer up to 12 hours of protection while several lower concentration DEET formulations (20%-34%) offered 3-6 hours of protection.[1] Other research has corroborated the effectiveness of DEET.[2]

Effects on health

DEET is the most common active ingredient in insect repellents.

The American Academy of Pediatrics found no difference in safety for children, between products containing 10% and 30% DEET, when used as directed, but recommends that DEET not be used on infants less than two months old.[3]

As a precaution, manufacturers advise that DEET products should not be used under clothing or on damaged skin, and that preparations be washed off after they are no longer needed or between applications.[3] In rare cases, it may cause skin reactions.[3]

In the DEET Reregistration Eligibility Decision (RED), the EPA reported 14 to 46 cases of potential DEET-associated seizures, including 4 deaths. The EPA states: " does appear that some cases are likely related to DEET toxicity," but observed that with 30% of the US population using DEET, the likely seizure rate is only about one per 100 million users.[4]

A study which examined the risk factors for testicular cancer found evidence that use of insect repellents "mostly containing N,N-diethyl-m-toluamide (DEET)" were associated with an elevated risk of testicular cancer.[5]

The Pesticide Information Project of Cooperative Extension Offices of Cornell University states that "Everglades National Park employees having extensive Deet exposure were more likely to have insomnia, mood disturbances and impaired cognitive function than were lesser exposed co-workers". [6]

Effects on materials

DEET is an effective solvent, and may dissolve (part of) some plastics, rayon, spandex, other synthetic fabrics, leather, and painted or varnished surfaces.[citation needed]

Effects on the environment

Although few studies have been conducted to assess possible effects on the environment, DEET is a moderate chemical pesticide and may not be suitable for use in and around water sources. Though DEET is not expected to bioaccumulate, it has been found to have a slight toxicity for coldwater fish such as the rainbow trout[7] and the tilapia [8], and it has also been shown to be toxic for some species of freshwater zooplankton.[9] DEET has been detected in significant levels in waterbodies as a result of production and use, such as in the Mississippi River and its tributaries, where a 1991 study detected levels varying from 5 to 201 ng/L. [10]

Natural alternatives

A test of various marketed insect repellents by an independent consumer organization found that synthetic repellents, including DEET, were more effective than repellents with ‘natural’ active ingredients. All the synthetics gave almost 100% repellency for the first 2 hours, whereas the natural repellent products were most effective for the first 30-60 minutes and required reapplication to be effective over several hours.[11]

Citronella oil has been used as an insect repellent for 60 years.[12] Its mosquito repellency qualities have been verified by research,[13] [14][15] however, the repellency duration of DEET is much greater.[16] While most essential oil based repellents are not as effective as DEET,[16][17] research also shows that some EO-based formulas can be comparable to DEET, and somewhat better. [18]

See also


  • M. S. Fradin (1998). "Mosquitoes and Mosquito Repellents: A Clinician's Guide". Ann Intern Med 128 (11): 931-940.
  1. ^ Matsuda, Brent M.; Surgeoner, Gordon A.; Heal, James D.; Tucker, Arthur O.; Maciarello, Michael J. (1996). "Essential oil analysis and field evaluation of the citrosa plant "Pelargonium citrosum" as a repellent against populations of Aedes mosquitoes.". Journal of the American Mosquito Control Association 12 (1): 69-74.
  2. ^ University of North Carolina (3 Jul 02). "Independent study: DEET products superior for fending off mosquito bites". Press release.
  3. ^ a b c Insect Repellent Use and Safety. West Nile Virus. Centers for Disease Control and Prevention (12 Jan 07).
  4. ^ "Reregistration Eligibility Decision: DEET." U.S. Environmental Protection Agency, Office of Prevention, Pesticides, and Toxic Substances. September 1998. pp39-40
  5. ^ M. Walschaerts, A. Muller, J. Auger, L. Bujan, J.-F. Guerin, D. L. Lannou, A. Clavert, A. Spira, P. Jouannet and P. Thonneau (2007). "Environmental, occupational and familial risks for testicular cancer: a hospital-based case-control study". International Journal of Andrology 30 (4): 222-229. doi:10.1111/j.1365-2605.2007.00805.x.
  6. ^ DEET. Pesticide Information Profile. EXTOXNET (Oct 1997). Retrieved on 2007-09-26.
  7. ^ U.S. Environmental Protection Agency. 1980. Office of Pesticides and Toxic Substances. N,N-diethyl-m-toluamide (Deet) Pesticide Registration Standard. December, 1980. 83 pp.
  8. ^ Mathai, AT; Pillai, KS; Deshmukh, PB (1989). "Acute toxicity of deet to a freshwater fish, Tilapia mossambica : Effect on tissue glutathione levels.". Journal of Environmental Biology 10 (2): 87-91..
  9. ^ J. Seo, Y. G. Lee, S. D. Kim, C. J. Cha, J. H. Ahn and H. G. Hur (2005). "Biodegradation of the Insecticide N,N-Diethyl-m-Toluamide by Fungi: Identification and Toxicity of Metabolites". Archives of Environmental Contamination and Toxicology 48 (3): 323-328. doi:10.1007/s00244-004-0029-9.
  10. ^ Errol Zeiger, Raymond Tice, Brigette Brevard, (1999) N,N-Diethyl-m-toluamide (DEET) [134-62-3] - Review of Toxicological Literature. Retrieved on July 20.
  11. ^ Test: Mosquito repellents. CHOICE (Dec 2005). Retrieved on 2007-09-26.
  12. ^ Citronella (Oil of Citronella) (021901) Fact Sheet. U.S. Environmental Protection Agency (Nov 1999). Retrieved on July 20, 2007.
  13. ^ Jeong-Kyu KIM, Chang-Soo KANG, Jong-Kwon LEE, Young-Ran KIM, Hye-Yun HAN, Hwa Kyung YUN (2005). "Evaluation of Repellency Effect of Two Natural Aroma Mosquito Repellent Compounds, Citronella and Citronellal". Entomological Research 35 (2): 117-120. doi:10.1111/j.1748-5967.2005.tb00146.x.
  14. ^ Ibrahim Jantan, and Zaridah Mohd. Zaki, Development of environment-friendly insect repellents from the leaf oils of selected Malaysian plants, ASEAN Review of Biodiversity and Environmental Conservation (ARBEC), May 1998.
  15. ^ Trongtokit Y, Rongsriyan Y, Komalamisra N, Apiwathnasom L (2005). "Comparative repellency of 38 essential oils against mosquito bites". Phytother Res. 19 (4): 303-9. doi:10.1002/ptr.1637.
  16. ^ a b M. S. Fradin and J. F. Day (2002). "Comparative Efficacy of Insect Repellents against Mosquito Bites". N Engl J Med 347 (1): 13-18. doi:10.1056/NEJMoa011699.
  17. ^ Collins, D.A.; Brady, J.N.; Curtis, C.F. (1993). "Assessment of the efficacy of Quwenling as a Mosquito repellent". Phytotherapy Research 7 (1): 17-20.
  18. ^ Trongtokit Y.; Rongsriyam Y, Komalamisra N, Krisadaphong P, Apiwathnasorn C, Krisadaphong P, Apiwathasorn C, (2004). "Laboratory and field trial of developing medicinal local Thai plant products against four species of mosquito vectors". Southeast Asia J, Trop Med Public Health 35 (2): 325-33. PMID 15691131.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "DEET". A list of authors is available in Wikipedia.
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