Several common household products can kill spiders on contact, and a few natural options work as repellents to keep them from coming back. The most effective approach combines direct-kill methods for spiders you can see with prevention strategies that reduce their numbers over time. Here’s what actually works, what doesn’t, and how to use each method safely.
Vinegar Spray for Direct Contact
White vinegar is one of the easiest spider-killing options already in your kitchen. The acetic acid damages a spider’s nervous system on contact and causes dehydration, which can be fatal. Mix equal parts white vinegar and water in a spray bottle and spray directly onto any spider you see.
The key limitation: vinegar works primarily as a contact killer, meaning you need to hit the spider directly. As a residual repellent, it’s less reliable. The strong smell fades as it dries, and its deterrent effect fades with it. Spray it along windowsills, door frames, and corners where you’ve noticed webs, but plan to reapply every few days.
Dish Soap and Water
A simple soap spray is surprisingly effective. Mix one to two teaspoons of liquid dish soap into a pint of water and spray spiders directly. Soap works in two ways: it breaks down the waxy coating on a spider’s body, causing it to lose moisture rapidly, and it disrupts the surface tension of water so the liquid penetrates the spider’s respiratory openings. This essentially suffocates the spider while dehydrating it at the same time.
Soap spray is safe around food prep areas and won’t stain surfaces, making it a good option for kitchens and bathrooms. It leaves no toxic residue, but like vinegar, it only works on contact. It won’t prevent new spiders from moving in.
Peppermint Oil as a Repellent
Peppermint oil is one of the few natural repellents with actual research behind it. A 2018 study tested peppermint oil against three spider species and found it strongly repelled two of them. The third species was less sensitive but still showed some avoidance behavior. To make a spray, add about five drops of peppermint oil to a 16-ounce spray bottle filled with water and a small squirt of dish soap, then shake well. The soap helps the oil mix with the water instead of floating on top.
Spray this mixture around entry points, window frames, baseboards, and any corners where spiders tend to build webs. Reapply once a week or whenever the scent fades. Peppermint oil won’t kill spiders outright, but it discourages them from settling in treated areas.
One note on other essential oils: lemon oil is frequently recommended online, but the same 2018 study found it had no repellent effect on any of the spider species tested. If you want to try alternatives beyond peppermint, clove oil has shown stronger results in studies on ticks and mites, and thyme oil also demonstrated pesticidal activity against related arachnids.
Diatomaceous Earth for Long-Term Control
Food-grade diatomaceous earth is a fine powder made from fossilized algae. Under a microscope, each particle has razor-sharp edges that cut through a spider’s exoskeleton. Once the outer shell is damaged, the powder absorbs the oils and fats from the spider’s protective coating, causing it to dehydrate and die. This process isn’t instant. It can take anywhere from a few hours to a couple of days, but it works on any spider that walks through it.
Dust a thin layer along baseboards, behind furniture, in closets, under beds, and in any cracks or gaps where spiders travel. A light coating works better than a thick pile, because spiders will walk around a visible mound of powder. The product keeps working as long as it stays dry, so it’s especially useful in basements, garages, and attics.
Use only food-grade diatomaceous earth, not the pool-grade version, which is chemically treated and unsafe for home use. Even with food-grade products, the dust can irritate your nose, throat, eyes, and skin. Wear a simple dust mask while applying it and keep the area ventilated. The FDA lists food-grade diatomaceous earth as “Generally Recognized as Safe,” but breathing in large amounts can cause coughing and shortness of breath.
Safety Around Pets and Children
If you have cats, be very cautious with essential oils. Tea tree oil is especially dangerous for cats because they lack the liver enzyme needed to metabolize it. Even indirect exposure, like a cat grooming a dog that’s been treated with tea tree oil, can cause serious illness. Peppermint oil is generally considered lower risk, but cats are more sensitive to essential oils overall than dogs are. Birds should never be exposed to essential oils at all.
Diatomaceous earth is low-toxicity for mammals, but keep pets out of the room while you’re applying it so they don’t inhale the airborne dust. Once the powder has settled into cracks and along baseboards, the risk drops significantly. Vinegar and dish soap sprays are the safest options in homes with pets or small children.
Seal Entry Points to Stop New Spiders
Killing individual spiders only goes so far if your home keeps inviting new ones in. Spiders can squeeze through gaps as small as 1/16 of an inch, so sealing entry points makes a real difference. The University of Kentucky’s entomology department recommends starting with these areas:
- Exterior doors: Install door sweeps on all outside doors. Lie on the floor and check for light coming under the door. If you see any, spiders can get through.
- Windows: Caulk cracks around window frames with silicone or acrylic latex caulk. Repair any tears in screens.
- Utility openings: Seal gaps where pipes, wires, outdoor faucets, dryer vents, and cable lines enter the foundation. Use caulk, expandable foam, or copper mesh.
- Garage doors: Fit the bottom with a rubber seal. Vinyl seals crack in cold weather and leave gaps.
- Sliding glass doors: Line the bottom track with half-inch to three-quarter-inch foam weatherstripping.
Beyond sealing, reduce what attracts spiders in the first place. Outdoor lighting draws the insects that spiders feed on, so switching to yellow or sodium vapor bulbs near doors cuts down on the prey that lures spiders close to your home. Clearing wood piles, leaf litter, and dense vegetation from your foundation removes hiding spots. Inside, regular vacuuming destroys webs, egg sacs, and the spiders themselves.
What Doesn’t Work
Horse chestnuts (also called conkers) are one of the most repeated spider repellent tips online. The Royal Society of Chemistry once held a contest to find evidence for or against the claim. The winning entry came from a group of fifth graders who demonstrated that spiders walked over chestnuts without hesitation, showing no avoidance compared to other materials. Lemon oil, as mentioned earlier, also failed to repel any spider species in controlled testing despite being widely recommended.
Ultrasonic plug-in devices marketed as spider repellents have similarly weak evidence behind them. Most independent testing shows no meaningful effect on spider behavior.
When a Spider Might Be Dangerous
Most house spiders are harmless, but two groups in North America deserve caution. Black widows are shiny black with a red hourglass marking on the underside of the abdomen. Mature females are about half an inch long. Their venom is a neurotoxin that causes radiating pain from the bite site, and severe cases can involve nausea, body aches, sweating, and labored breathing.
Brown recluse spiders are yellowish to grayish brown with a dark violin-shaped marking on the area behind their head. They’re smaller, about a quarter to half an inch in body length, though their long legs make them look bigger. Their venom destroys surrounding tissue, producing a blister that can develop into an open ulcer, sometimes accompanied by fever and restlessness.
If you’re finding either of these species in your home, home remedies alone may not be sufficient. A professional pest control treatment, combined with thorough sealing of entry points, is the more reliable path to clearing an infestation of medically significant spiders.