By Hanie Elfenbein, DVM
Fleas are itchy and uncomfortable for our pets, but they are easily preventable. Options to protect your pet from fleas include collars, topical treatments, and chewable tablets. Nowadays, some of these preventatives last as long as 12 weeks.
Some pet parents opt to use natural topical flea treatments, such as tea tree oil. However, tea tree oil can be toxic for pets if ingested or used improperly. Your veterinarian can help you decide what’s right for you and your pet.
Is tea tree oil safe as a topical flea treatment?
Home remedies for fleas are generally inadvisable for both safety and efficacy reasons. Commercially available flea treatments from your veterinarian are safety tested under strict conditions. In addition, they are proven to be effective at preventing and killing fleas. Essential oils and extracts like tea tree, eucalyptus, and citronella do not require testing for safety or efficacy, nor are the contents of the bottle regulated. That means you may not get what you are paying for, and have no guarantee that it will work.
But can tea tree oil kill and repel fleas?
When diluted and used safely, tea tree oil can kill and repel fleas. But it is among the herbal treatments listed as “especially risky” in the Merck Veterinary Manual. This is because tea tree oil is difficult to dilute properly in home kitchens.
Commercially available formulas for pets contain only 0.1 to 1 percent tea tree oil. Even if you measure everything precisely and shake the bottle before spraying it on your dog’s coat, it is easy to apply more than intended. If your cat or dog licks the oil off, which pets tend to do as they groom, your pet could get very sick.
Store-bought shampoos containing tea tree oil have very small amounts of tea tree oil. The product is formulated so that the oil is evenly distributed, reducing the toxic risk to pets.
Aren’t topical flea products more toxic than tea tree oil?
Most topical flea products recommended by veterinarians use a type of chemical that targets molecules found in the body of insects that are not found in mammals. That’s what makes them safe to use on our pets and good at killing fleas quickly in the small doses applied to skin or ingested.
There is another category of chemicals that are toxic to some mammals but not others. For example, some tick products contain a class of chemical called permethrins that are safe to use on dogs but are toxic to cats. Tea tree oil falls into this category: it can be toxic to our pets and fleas, even though it is likely safe for most humans when used on the skin. The dose required to kill all of the fleas might be fatal to your cat.
Another reason commercially available flea treatments are preferred over essential oils like tea tree is that some contain chemicals that actually stop the development of the next generation of fleas. That means any eggs a female lays before she is killed by the flea treatment will not be able to hatch. No adults + no eggs = no more fleas.
What are some safer alternatives for repelling fleas?
One home remedy that may be safer than tea tree oil is diatomaceous earth. This is a long name for fossilized algae. It works by creating holes in bugs like cockroaches, snails, fleas, and even some kinds of worms. Diatomaceous earth has long been used around vegetable gardens to keep bugs out and is often fed to horses and livestock to help treat intestinal worms. Since it is safe to consume in specific quantities (consult a veterinarian or physician), it is much safer to use on your pet than something like tea tree oil, which is toxic when ingested even in small quantities.
If you choose to administer a home treatment like diluted tea tree oil, please consult your veterinarian first. Your doctor not only knows the science but also is familiar with your pet and your lifestyle, and can help you make the best choice for your family.