Peppermint oil does appear to repel some spider species, but the evidence is limited and the effect isn’t universal. In controlled lab tests, peppermint oil repelled two out of three spider species tested, with those species avoiding it in more than 75 percent of trials. That’s a meaningful result, but it comes with important caveats about which spiders respond, how long the effect lasts, and whether a lab result translates to your home.
What the Research Actually Found
The most direct study on this question was published in 2018 in the Journal of Economic Entomology. Researchers at the University of Ulm and the University of Toronto tested the top three natural spider repellents recommended online: peppermint oil, lemon oil, and chestnuts. They placed adult female spiders in a Y-shaped tube where one arm contained the test substance and the other was empty, then recorded which direction the spider chose.
Brown widow spiders and European garden spiders avoided peppermint oil in more than 75 percent of tests. That’s a strong result. But the third species tested, a common house spider relative called Steatoda grossa, showed no significant response to peppermint oil at all. The spider simply didn’t care.
Lemon oil, despite being the most frequently recommended natural spider repellent online, had no measurable effect on any of the three species. Chestnuts performed about as well as peppermint oil, repelling the same two species effectively.
One critical detail from the study: all three spider species tested are sedentary web-builders. The researchers noted that the repellent effect only applied to keeping spiders from entering an area. Peppermint oil may not drive out a spider that has already settled in and built a web. If you’re trying to evict an established resident, the scent alone probably won’t do it.
Why Results Vary by Spider Species
Spiders sense their environment primarily through chemical receptors on their legs and specialized sensory hairs. Different species have different sensitivities to volatile compounds, which explains why peppermint oil works on some spiders and not others. The menthol and other compounds in peppermint oil that irritate one species may be below the detection threshold or simply irrelevant to another.
This matters for practical use because the spiders in your home may or may not be among the species that respond to peppermint. Common house spiders, cellar spiders, and wolf spiders weren’t part of the study. It’s reasonable to try peppermint oil as a low-risk deterrent, but expecting it to work as a reliable barrier against all spiders isn’t supported by the evidence.
How to Make a Peppermint Spider Spray
If you want to try it, the standard approach is simple. Add about five drops of peppermint essential oil to a 16-ounce spray bottle filled with water. Add a small squirt of dish soap, which helps the oil mix with the water instead of floating on top, and shake well before each use.
Spray it along windowsills, doorframes, baseboards, and any cracks or gaps where spiders might enter. Start with once a week. If you notice spiders returning before the week is up, increase to every few days. The scent fades as the oil evaporates, so reapplication is necessary to maintain any deterrent effect. Indoors, the smell dissipates within a day or two depending on ventilation.
Safety Concerns for Cats and Dogs
Peppermint oil is toxic to cats. Cats lack certain liver enzymes needed to metabolize essential oils, making them especially vulnerable. Peppermint oil is on the Pet Poison Helpline’s list of essential oils known to cause poisoning in cats, with potential symptoms including drooling, vomiting, tremors, wobbliness, respiratory distress, low heart rate, and in severe cases, liver failure.
Even passive exposure carries risk. If you’re diffusing peppermint oil or spraying it in a room where a cat spends time, the microdroplets can collect on the cat’s fur and be ingested during grooming. Inhaling strong concentrations can cause watery eyes, a burning sensation in the nose and throat, nausea, and labored breathing. Concentrated essential oils should never be applied directly to a cat’s skin.
Dogs are generally less sensitive than cats but can still experience gastrointestinal upset or skin irritation from direct contact with undiluted peppermint oil. If you have pets, especially cats, this is a significant reason to skip the peppermint approach entirely.
More Effective Ways to Reduce Spiders
Spiders follow their food. If your home has flies, gnats, moths, or other small insects, spiders will show up to eat them. Reducing insect populations by fixing window screens, sealing gaps around doors, and keeping outdoor lights off (or switching to yellow bulbs that attract fewer insects) does more than any repellent spray.
Removing existing webs with a vacuum or duster encourages spiders to relocate, since rebuilding a web costs significant energy. Clearing clutter in basements, garages, and closets eliminates the sheltered spots spiders prefer. Sealing cracks in your foundation, around pipes, and along window frames physically blocks entry points rather than relying on a scent that fades in days and only works on some species.
Sticky traps placed along walls and in corners can catch wandering spiders and also help you identify which species you’re dealing with. For significant infestations, particularly of venomous species like brown recluses, professional pest control offers targeted treatments that peppermint oil simply can’t match.