There are many "all-natural" remedies that are touted as being effective in killing fleas and essential oils are often posed as alternatives to medications. Fleas are bothersome, bite you and your pets, and carry diseases, so it's good to prevent them and kill them if you find them. But not all treatments are safe and effective. Many pet owners used tea tree oil to treat fleas, but it's important to know whether this oil is going to actually work and not cause harm to your pet.
What Is Tea Tree Oil?
Also referred to as Malaleuca, tea tree oil is from the Australian tea tree plant, Melaleuca alternifolia. It is an essential oil with a minty smell that has historically been used in diluted amounts to treat various skin issues in people. In pets, it is also sometimes used to manage skin conditions as well as to kill parasites, such as fleas.
Tea tree oil should never be given orally as it is toxic if swallowed. Keep tea tree oil out of your pet's reach at all times.
How Does Tea Tree Oil Work?
Terpenes are specific components of tea tree oil that have been found to be beneficial. One terpene found in tea tree oil is called terpinen-4-ol and it is known to have antibacterial and antifungal effects in people through the activation of white blood cells. 1,8-cineole is another type of terpene found in tea tree oil that has shown to be relatively effective in killing various types of parasites, and limonene, yet another type of terpene, has been found to specifically kill Ctenocephalides felis, the species of flea most commonly found on pets.
Different types of terpenes are found in various plants and are also responsible for the way a plant smells. This means terpenes are responsible for essential oils having strong scents but they also work in the endocannabinoid system within the body. The endocannabinoid system helps regulate many bodily functions but research is ongoing to fully understand exactly how this system works. The terpenes are why tea tree oil may be an effective alternative remedy.
Does Tea Tree Oil Kill Fleas?
There is no published, scientific evidence that whole tea tree oil specifically kills fleas, but the oil has been shown to be effective in killing other types of arthropods, such as some species of ticks and lice. Additionally, since one natural component of tea tree oil, limonene, has been shown to be effective against fleas, it is often assumed that tea tree oil as a whole will also be effective.
Is Tea Tree Oil Safe for Pets?
Tea tree oil is toxic if swallowed, so it should never be administered orally to a pet or person. If a pet licks tea tree oil that has been spilled or sprayed elsewhere, it could be very harmful. Additionally, if tea tree oil is applied to a pet's skin in large quantities or undiluted, it may cause muscle tremors, weakness, a low body temperature, drooling, and problems walking. The Pet Poison Helpline has reported that as few as seven drops of undiluted tea tree oil on a pet's skin has caused serious issues so undiluted oil can be very dangerous.
On the other hand, tea tree oil in diluted amounts can be found in some pet products and can be safe, but these dilutions should not exceed 1%. Stronger solutions should never be used and you should ensure diluted products still contain the beneficial terpenes limonene and 1,8-cineole which may be effective against fleas.
How Do You Safely Use Tea Tree Oil?
Before using tea tree oil on your pet you should discuss it with your veterinarian to ensure it is recommended and safe for it. If your vet decides it's okay for you to use tea tree oil, be sure to never get it in or near your pet's mouth and only ever use a 1% or less dilution. If your pet grooms itself, be careful not to apply the diluted oil in places where it can be licked off before it can dry. Because cats groom themselves so heavily, the concern for tea tree oil toxicity in cats, even when applied topically, is much higher than it is for dogs.
Bischoff K, Guale F. Australian tea tree (melaleuca alternifolia) oil poisoning in three purebred cats. J VET Diagn Invest. 1998;10(2):208-210.
Budhiraja SS, Cullum ME, Sioutis SS, Evangelista L, Habanova ST. Biological activity of Melaleuca alternifolia (Tea tree) oil component, terpinen-4-ol, in human myelocytic cell line HL-60. Journal of Manipulative and Physiological Therapeutics. 1999;22(7):447-453.
Conti, B., Flamini, G., Cioni, P.L. et al. Mosquitocidal essential oils: are they safe against non-target aquatic organisms?. Parasitol Res 113, 251–259 (2014). https://doi.org/10.1007/s00436-013-3651-5
Collart MG, Hink WF. Sublethal effects of D-limonene on the cat flea, Ctenocephalides felis. Entomologia Experimentalis et Applicata. 1986;42(3):225-229.
Ellse L, Wall R. The use of essential oils in veterinary ectoparasite control: a review: Essential oils in veterinary ectoparasite control. Med Vet Entomol. 2014;28(3):233-243.