Essential Oils for Mosquitoes, Bugs and Lice: What the Research Shows

Safety first. Where mosquitoes or ticks carry disease, protection means more than a pleasant smell. The CDC recommends proven EPA-registered insect repellents and says it does not know the effectiveness of non-EPA registered repellents, including some natural ones. [1] Do not use products containing oil of lemon eucalyptus (OLE) or PMD on children under 3 years old, according to the CDC. [1] Do not swallow essential oils. If anyone has, call Poison Help at 1-800-222-1222; call 911 for collapse, a seizure or trouble breathing. [2]

Mosquitoes

What EPA and CDC say. The EPA's list of skin-applied repellent ingredients includes oil of citronella, catnip oil and oil of lemon eucalyptus (which contains PMD but is regulated as a separate pesticide chemical). [4] A registered product has a registration number, and the EPA says the label is your guide to using it safely and effectively. [5] The EPA also notes that some lemon eucalyptus products should not be used on children under three. [5]

Plant names. Citronella oils come from Cymbopogon nardus (L.) Rendle or Cymbopogon winterianus Jowitt ex Bor, both accepted names in GBIF. [6] Lemon eucalyptus is Corymbia citriodora (Hook.) K.D.Hill & L.A.S.Johnson; the older name Eucalyptus citriodora is a synonym. [6] "Lemon eucalyptus" is not the same as ordinary eucalyptus oil; see Eucalyptus oil.

A claim that a pure oil "works like DEET" is therefore not supported by the sources we read. Older tests of plant oils in laboratories cannot show how long a person is protected outdoors. For more on peppermint, see Peppermint oil for spiders, mice and other pests, and for lemongrass, see Lemongrass oil.

Ticks

Tick bites can transmit disease. The CDC lists EPA-registered repellents, including oil of lemon eucalyptus, as proven safe and effective when used as directed, even for pregnant and breastfeeding women, and repeats the warning that OLE or PMD products should not be used on children under 3. [8] Proper evidence not found in the sources we read for essential oils alone preventing tick bites: the CDC page does not mention natural or plant-based products. Because tick-borne illness can be serious, use a registered repellent from the EPA list rather than an unregistered oil, and ask a pharmacist or clinician about choices for children and pregnancy.

Head lice

What the NHS says. Head lice are found by spotting live lice, and the NHS says wet combing can remove lice and nits. [9] The NHS lists treatments not recommended because they are unlikely to work, including plant oil treatments such as tea tree, eucalyptus and lavender oil herbal remedies. [9]

What trials found. Two small Australian randomized trials tested commercial lice treatments containing oils, not pure oils:

• A 2010 trial of 123 people with live head lice compared a product containing tea tree oil and lavender oil with a pyrethrin-based product and a "suffocation" product. 41 of 42 (97.6%) using the tea tree and lavender product were louse-free one day after the last treatment. [10]


• A 2018 trial reported that a eucalyptus and Leptospermum petersonii product was more than twice as effective as a pyrethrin product in per-protocol participants. Adverse events were limited to transient itching, burning or stinging. [11] The article carries a company copyright notice. [11]

These are products designed for lice, tested under trial conditions; the trials do not tell readers to mix oils at home. The conflict with the NHS page is a real difference of opinion in the sources: we did not find an independent review resolving it, so we cannot say which view is right. Ask a pharmacist or clinician about a product for children. Poison Control says children have thin skin and immature livers, which might make them more susceptible to toxic effects. [2]