Several household ingredients can kill or repel ants without posing serious risks to kids or pets. The most effective non-toxic options work in different ways: some destroy ants on contact, some dehydrate them over days, and some act as slow-killing baits that get carried back to the colony. Your best choice depends on whether you’re dealing with a trail of kitchen ants or a larger infestation.
Soapy Water: The Best Contact Killer
A simple spray bottle of water with a few squirts of dish soap is the fastest non-toxic way to kill ants you can see. The soap breaks down the protective waxy coating on the ant’s body, causing it to dry out and die. It also disrupts the surface tension of water, allowing liquid to flood the ant’s tiny breathing openings and essentially drown it. Oregon State University recommends wiping up foraging ants with soapy water and a sponge to eliminate them before they return to the nest and recruit more.
The limitation is obvious: soapy water only kills ants it touches. It does nothing about the colony sending them. Think of it as your first line of defense for clearing visible trails while you set up a longer-term solution.
Borax and Boric Acid Baits
Boric acid is the closest thing to a guaranteed ant killer you can make at home, and it’s the only DIY method that reliably destroys entire colonies. It works as a slow-acting stomach poison. Ants eat the bait, carry it back to the nest, and share it with the queen and other workers before it kills them. This process takes time, often one to two months for full colony elimination.
The University of Hawaiʻi’s tested recipe calls for 1 teaspoon of boric acid powder mixed with 3 tablespoons of white sugar, dissolved in just under 2 cups of warm distilled or bottled water. Soak cotton balls in the mixture and place them in small containers near ant trails. Check weekly and replace any stations that get moldy. The sugar draws ants in; the low concentration of boric acid ensures they survive long enough to bring the poison home.
A Note on Safety
Boric acid is often labeled “natural” or “least-toxic,” and at bait concentrations it poses minimal risk. But it isn’t completely harmless. According to the Agency for Toxic Substances and Disease Registry, ingesting large amounts (around 30 grams of boric acid) can damage the stomach, intestines, liver, kidneys, and brain. That’s far more than a bait station contains, but it’s worth keeping stations out of reach of toddlers and pets who might drink the sugar water. Boric acid belongs in a category best described as “low toxicity when used correctly” rather than truly non-toxic.
Diatomaceous Earth
Food-grade diatomaceous earth is a fine powder made from fossilized algae. At a microscopic level, the particles have sharp edges that scratch through an ant’s waxy outer coating, causing it to lose moisture and die from dehydration over a period of days. It contains no chemical pesticides and is safe to handle with bare skin.
The catch: it has real limitations. Oklahoma State University notes that diatomaceous earth will kill some ants but is not very effective when the soil is moist, and it rarely eliminates colonies when used alone. It works best as a dry barrier in cracks, along baseboards, or around entry points indoors. If you’re sprinkling it outside where rain or sprinklers can dampen it, you’ll need to reapply frequently. Pair it with a bait strategy for better results.
Essential Oils as Repellents
Essential oils won’t kill ants, but certain ones can keep them away from specific areas. Cinnamon oil and lemon juice are the two strongest repellents tested in controlled studies. Cinnamon oil extract performed significantly better than other forms of cinnamon, while lemon juice outperformed lemon oil. Peppermint, basil, and lemongrass oils also show repellent effects against various insects.
To use them, mix 10 to 15 drops of cinnamon or peppermint oil with water in a spray bottle and apply along windowsills, doorframes, and countertop edges where ants enter. You’ll need to reapply every few days as the scent fades. This approach is useful for keeping ants out of a pantry or away from a pet’s food bowl, but it won’t solve an infestation because the colony remains active somewhere else.
Baking Soda and Other Home Remedies
You’ll find plenty of advice online about mixing baking soda with powdered sugar to kill ants. The idea is that sugar attracts them and baking soda reacts with their acidic digestive systems, killing them from the inside. While this mechanism is plausible and some people report success, there are no university-backed studies confirming it works reliably. The same goes for cornstarch, cream of wheat, and similar pantry remedies that are said to expand inside an ant’s body.
If you want to try baking soda, mix it 1:1 with powdered sugar and place small amounts in shallow lids near ant trails. It costs nothing and carries zero toxicity risk. Just don’t rely on it as your only strategy if you have a persistent problem.
Why the Type of Ant Matters
Most kitchen ant problems involve small species attracted to sugar and grease. For these ants, the sugar-boric acid bait recipe above is highly effective because they eagerly consume sweet liquids and share them with nestmates. Wiping trails with soapy water, sealing entry points, and placing bait stations is usually enough to resolve things within a few weeks.
Carpenter ants are a different story. They nest inside damp or damaged wood in your home’s structure, and their food preferences are more complex. Oregon State University warns that carpenter ants may not be attracted to standard bait food sources, so success with DIY baits varies. Because they actively damage wooden structures, carpenter ant problems typically require more than non-toxic remedies. You’ll need to find and eliminate the moisture source, repair damaged wood, seal entry points, and often treat the nesting area directly.
Putting It All Together
The most effective non-toxic approach combines several methods. Start by cleaning up food sources and wiping existing trails with soapy water to disrupt the scent paths ants follow. Set out boric acid bait stations near areas of activity and leave them undisturbed for weeks. Use diatomaceous earth as a dry barrier in cracks and gaps where ants enter. Apply essential oil sprays to high-priority areas like countertops where you don’t want ants at all.
Patience matters more than any single product. Baits need time to circulate through a colony, and killing foragers on the surface without addressing the nest just means more will come. Resist the urge to spray foragers near your bait stations. You want those ants alive and carrying poisoned food home. If you’ve been consistent for two months with boric acid baits and still see heavy activity, you’re likely dealing with a species or colony size that needs professional treatment.