The most effective way to get rid of ants in your house is with slow-acting bait that workers carry back to the colony, killing the queen and the entire nest over one to several weeks. Sprays and repellents kill the ants you can see, but the colony simply sends more. Baits work with ant biology instead of against it, and combining them with basic prevention keeps ants from coming back.
Why Baits Work Better Than Sprays
Ants live in colonies that can number in the thousands or hundreds of thousands. The workers trailing across your kitchen counter are a tiny fraction of the population. Killing them with a spray does almost nothing to the colony itself, which keeps producing replacements. This is why the most reliable approach targets the nest, not just the visible ants.
Ant baits exploit a behavior called trophallaxis: workers find food, carry small portions back to the nest, and pass it mouth to mouth to other workers, larvae, and queens. A bait mixes an attractant (usually something sugary or protein-rich) with a slow-acting toxicant. The slow action is the key. If the poison kills too fast, workers die before reaching the nest and the colony is never exposed. With the right bait, you want to keep seeing ants for a while. That means they’re still ferrying poison home. Expect to see fewer ants within 5 to 10 days, but complete control can take several weeks.
Choosing the Right Bait
Common active ingredients in store-bought ant baits include boric acid (borate), fipronil, avermectin, and hydramethylnon. They all work on the same slow-kill principle, but the formulation matters more than the ingredient name. Prepackaged bait stations typically contain about 5.4% borate. They’re convenient and can knock out foragers inside the home, but for a heavy infestation they often kill workers too quickly for the poison to spread deep into the colony.
Liquid borate baits with a lower concentration, around 0.5 to 1.0% borate in sugar water, are more effective for serious problems. The lower dose lets more workers survive the trip back to the nest, which means more poison reaches the queen. These come in refillable bait stations and work especially well for sugar-loving species like Argentine ants and odorous house ants. Place them along ant trails, near entry points, and anywhere you see heavy activity. Don’t spray insecticide near the bait stations, because that repels ants away from the bait you want them to eat.
Identifying What You’re Dealing With
Not all ants respond to the same treatment, so a quick identification helps you choose the right approach.
- Odorous house ants are medium-sized, smooth-bodied, and produce a licorice-like smell when crushed. They love sweets and are one of the most common indoor invaders. Standard sugar-based baits work well on them.
- Pharaoh ants are tiny (about 1/32 inch), yellowish with a dark-tipped abdomen. They’re picky eaters that alternate between sugary and protein-rich foods, so you may need specially designed pharaoh ant baits that offer both.
- Carpenter ants are large (1/4 to 1/2 inch), black or black-and-red, and nest inside wood. They hollow out structural timber, doors, and wall cavities. Because they have such a varied diet, baits usually aren’t successful against them. Carpenter ant infestations typically require locating the nest and treating it directly with a dust insecticide, and serious cases warrant professional help.
- Crazy ants move erratically and fast, with noticeably long legs and antennae. Indoors, check the soil of potted plants for nests.
- Fire ants are reddish-brown with workers ranging from 1/16 to 3/16 inch. They almost always nest outdoors in conspicuous mounds but enter homes looking for food and water in late summer.
Natural and Low-Toxicity Options
If you prefer to avoid conventional insecticides, a few alternatives can help, though each comes with trade-offs.
Food-grade diatomaceous earth (DE) kills ants mechanically rather than chemically. The microscopic sharp edges of the powder cut through an ant’s waxy exoskeleton, causing it to lose moisture and die from dehydration. Sprinkle a thin, even layer along ant trails, baseboards, windowsills, and under appliances. It loses effectiveness when wet, so vacuum up old powder and reapply every few days until the ants are gone. Always use food-grade DE. Pool-grade diatomaceous earth is processed differently and can be harmful to breathe.
White vinegar mixed with water and sprayed along entry points disrupts the pheromone trails ants use to navigate. This confuses foragers and can temporarily stop traffic along a trail. Peppermint oil, lavender oil, cinnamon, and lemon work on the same principle. The limitation is that none of these kill the colony. Once the scent fades, ants return and lay new trails. Think of them as a way to manage the problem day to day while baits do the deeper work, not as a standalone solution.
Making a Homemade Borate Bait
You can make an effective liquid bait by dissolving roughly 1% borax (by weight) into a sugar-water solution. That’s about half a teaspoon of borax per cup of warm water with a couple tablespoons of sugar stirred in. Soak cotton balls in the mixture and place them on small pieces of foil or in shallow lids near ant trails. The low borax concentration is important: too much kills workers before they share it. Replace the cotton balls every few days as they dry out.
This approach is inexpensive and matches the same principle behind commercial liquid borate bait stations. It works best against sugar-feeding species like odorous house ants and Argentine ants.
Safety Around Kids and Pets
Boric acid is low in toxicity for adults if touched or ingested in small amounts, but it’s not harmless. Eating it causes nausea, vomiting, and stomach pain, and children are more sensitive than adults. Infants exposed to boric acid over time are at risk for more serious effects, including seizures. Pets react similarly, and signs of poisoning can appear within two hours of ingestion.
Place bait stations and homemade baits in spots children and pets can’t reach: behind appliances, inside cabinets, on high shelves, or inside enclosed bait stations with small openings only ants can access. After placing baits, get down to floor level and look around to confirm nothing is within a child’s or pet’s reach.
Sealing Entry Points and Removing Attractants
Baits solve the current infestation. Prevention stops the next one. Ants are resourceful foragers, and a colony will keep sending scouts into your home as long as they find food, water, or easy access.
Start with sanitation. Wipe down counters after preparing food, store sugar, honey, and pet food in sealed containers, and don’t leave dirty dishes in the sink overnight. Even small crumbs behind a toaster or a sticky spot on the floor can sustain a foraging trail. Take out trash regularly and clean up pet food bowls after meals.
Next, seal the gaps ants use to enter. Common entry points include cracks around window frames, gaps where pipes or wires pass through walls, spaces under doors, and joints between the foundation and siding. Caulk small cracks and gaps with silicone sealant. Use weatherstripping under doors. Trim tree branches and shrubs that touch the house, since many ant species nest in trees and use branches as bridges to your walls.
Moisture draws ants indoors just as reliably as food does, especially in late summer. Fix leaky faucets, dry out under-sink areas, and make sure bathrooms are well ventilated. Carpenter ants in particular seek out damp or decaying wood for nesting, so addressing moisture problems in crawl spaces, attics, and around window frames makes your home far less attractive to them.