Peppermint oil is the most effective essential oil for repelling spiders, with lab studies showing it deters at least two spider species strongly enough to alter their behavior. But many oils commonly recommended online, especially lemon oil, have no scientific backing at all. Here’s what actually works, what doesn’t, and how to use it.
Peppermint Oil Has the Strongest Evidence
A 2018 study published in the Journal of Economic Entomology tested the three natural substances most frequently cited as spider repellents: peppermint oil, lemon oil, and chestnuts. Peppermint oil produced the clearest results. When brown widow spiders were exposed to mint oil in a two-choice test, 12 out of 15 chose the side without mint oil. Only two walked toward it. Nearly half of the spiders in the mint oil trials froze in place (a behavior called “huddling”) rather than move at all, which researchers interpreted as a strong avoidance response. Even among the spiders that didn’t freeze, about 68% still moved away from the mint oil.
Chestnuts also showed promise. A different species, the false black widow, showed a tendency to avoid chestnuts, with 73% choosing the control side, though this result didn’t reach statistical significance. The researchers concluded that both mint oil and chestnuts may be effective at deterring spiders from settling in an area, across at least two different spider families.
Lemon Oil Does Not Work
Despite being the most widely recommended natural spider repellent online (the study authors noted over a million Google hits for it at the time), lemon oil had no measurable effect on any of the spider species tested. Spiders walked toward it at the same rate as the control side. If you’ve been spraying lemon oil around your doorframes, it’s not doing anything to discourage spiders.
This is worth emphasizing because many DIY spider spray recipes call for citrus oils as a key ingredient. The popularity of this advice appears to be driven by repetition rather than evidence.
Why Some Oils Work and Others Don’t
Spiders detect chemicals in their environment through specialized sensory structures on their pedipalps, the small appendages near their mouths. Electrophysiological research on wolf spiders has confirmed these structures contain numerous chemical-sensing neurons. When a volatile compound like menthol (the active component in peppermint oil) reaches these sensors, the spider can detect it and choose to move away.
Not all spiders respond equally, though. The 2018 study found that one species (the false black widow) was less sensitive to mint oil than the brown widow. This means an oil that works well against one type of spider in your home may be less effective against another. There’s currently no controlled research showing essential oils repel medically significant species like brown recluses or black widows specifically.
How to Make a Peppermint Oil Spray
The basic recipe is simple: add 5 to 10 drops of peppermint essential oil to a 16-ounce glass spray bottle filled with water. Add a few drops of dish soap, which acts as an emulsifier to help the oil mix with the water instead of floating on top. Shake before each use.
Spray it along windowsills, doorframes, baseboards, and any cracks or gaps where spiders tend to enter. Reapply every few days, since the volatile compounds that repel spiders evaporate relatively quickly. A stronger concentration (closer to 10 drops) will last slightly longer and produce a more intense scent, but the oil dissipates regardless. Consistency matters more than concentration.
Use a glass bottle rather than plastic, as essential oils can break down certain plastics over time.
Essential Oil Safety Around Pets
If you have cats, dogs, or other pets, be cautious with any essential oil spray. In concentrated form, essential oils can cause unsteadiness, low body temperature, vomiting, diarrhea, and depression in dogs and cats. Animals that walk through oil residue or groom it off their fur are at risk. Tea tree oil is especially potent, with as few as seven or eight drops of the concentrated form potentially causing problems.
Birds are even more vulnerable. Their respiratory systems are highly sensitive to airborne compounds, so using an essential oil diffuser in a home with birds is a bad idea regardless of the oil type. For smaller pets like rabbits, guinea pigs, and hamsters, the same general cautions apply. If you’re spraying peppermint oil in areas your pets frequent, keep the concentration low, ensure good ventilation, and avoid applying it to surfaces your animals regularly contact.
What Else Actually Helps
Essential oils are best thought of as one layer in a broader approach, not a standalone solution. The volatile compounds evaporate within days, and their effectiveness varies by spider species. Pairing peppermint oil spray with physical deterrents will get better results.
- Seal entry points. Caulk gaps around windows, doors, and utility lines. Spiders follow insects indoors, and both need an opening to get in.
- Reduce outdoor lighting. Lights attract the insects spiders feed on. Switching to yellow or sodium vapor bulbs near entryways draws fewer bugs and, in turn, fewer spiders.
- Remove clutter. Spiders prefer undisturbed areas with cover. Clearing storage boxes, woodpiles near the house, and dense vegetation along your foundation removes the habitat they’re looking for.
- Diatomaceous earth. This fine powder made from fossilized algae damages the waxy coating on spider exoskeletons, causing dehydration. It works mechanically rather than chemically, so spiders can’t develop resistance to it. Apply it in thin layers along baseboards and in cracks where spiders travel.
Peppermint oil can discourage spiders from settling in a treated area, but it won’t eliminate an existing population. If you’re dealing with a significant number of spiders, particularly species you can’t identify, physical exclusion and habitat reduction will do more than any spray.