The best way to get rid of ants is to use slow-acting bait that workers carry back to the colony, killing the queen and the entire nest over days to weeks. Spraying ants you can see only kills the foragers, which represent a small fraction of the colony. The rest of the nest stays alive, and new foragers replace the dead ones. Bait works because it exploits the ants’ own food-sharing behavior against them.
Why Spraying Visible Ants Doesn’t Work
When you see a trail of ants across your kitchen counter, the instinct is to grab a spray can and wipe them out. This feels satisfying but accomplishes almost nothing. The ants you see are foragers, and they make up only a small proportion of the colony. The queen (sometimes multiple queens), the larvae, and thousands of additional workers remain safely in the nest, which could be behind your walls, under your foundation, or in your yard.
Spray insecticides create another problem: many are repellent. Rather than killing ants, they redirect them. The colony doesn’t die. It just reroutes its foraging trails, and you’ll see ants emerging from a different crack a few days later. Worse, if you spray near bait you’ve set out, you contaminate the bait and repel ants away from it, undermining the one strategy that actually works.
How Bait Eliminates the Whole Colony
Ant baits contain a food attractant (usually sugar or protein) mixed with a slow-acting toxicant. Foragers find the bait, eat some, and carry portions back to the nest. There, they feed it mouth-to-mouth to other workers, larvae, and critically, the queen. Because the poison acts slowly, foragers survive long enough to recruit more workers to the bait and distribute it widely through the colony before anyone starts dying.
This means you need to resist the urge to kill ants you see visiting the bait. Those ants are doing exactly what you want: ferrying poison home. You may continue seeing ants for a week or more after placing bait. That’s a sign the system is working, not failing. NC State Extension specifically advises against disturbing or spraying ants during active baiting, since doing so breaks the chain of transfer that kills the colony.
Choosing the Right Bait
Most ant species shift their dietary preferences seasonally, craving sugary foods at some times and greasy or protein-rich foods at others. If ants ignore your bait, they’re probably looking for the other type. Put out both a sugar-based bait and a protein or grease-based bait, and let the ants tell you which one they prefer by which they swarm.
Commercial bait stations, gel baits, and liquid baits all work. The key is the active ingredient’s speed. Look for products containing boric acid, fipronil, or indoxacarb. Fipronil-based baits can eliminate a colony within about a week, with worker activity dropping over 90% within three days. Indoxacarb takes roughly two weeks for full elimination. Boric acid is the slowest, sometimes requiring up to two months, but it’s widely available, inexpensive, and has low toxicity to mammals.
Place bait stations directly along ant trails and near entry points. More stations placed closer to activity will speed things up. Don’t move the stations once ants have found them.
A Simple DIY Bait Recipe
If you’d rather make your own bait, a well-tested formula from the University of Hawaiʻi uses just three ingredients:
- 1 teaspoon boric acid powder
- 3 tablespoons white sugar
- 1¾ cups warm distilled or bottled water (not tap water)
Stir until everything dissolves completely. Soak cotton balls in the solution and place them in shallow containers along ant trails. The low concentration of boric acid is what makes this effective. Too much boric acid kills foragers before they return to the nest. Too little won’t affect the colony. This ratio keeps the dose slow-acting enough for full distribution through the nest. Replace the cotton balls every few days so the bait stays fresh and appealing.
Keeping Pets Safe Around Bait
Ant baits use the same sugary attractants that appeal to dogs and cats. The active ingredients in most baits, including boric acid, fipronil, and imidacloprid, are toxic to pets at high enough doses. Boric acid irritates the digestive tract and, in large amounts, can damage the liver, kidneys, and nervous system. Fipronil and other neurotoxic ingredients can cause tremors, muscle twitching, and seizures at high exposure levels.
The good news is that the amount of toxicant in a single bait station is very small. A dog would need to consume a large quantity to reach dangerous levels. The lethal dose of boric acid in dogs is about 2,000 milligrams per kilogram of body weight, far more than what’s in a bait trap. Still, it’s smart to place bait stations in spots your pets can’t reach: behind the refrigerator, inside cabinets, under heavy furniture, or inside enclosed bait stations designed to let ants in while keeping larger animals out. Gel baits applied in thin lines along cracks and crevices are another pet-safer option since they’re harder for dogs and cats to access.
Sealing Entry Points and Removing Attractants
Bait solves the immediate problem. Prevention keeps ants from coming back. Start by figuring out where ants are entering. Follow trails back to their entry point, which is often a gap around a pipe, a crack in the foundation, or a space where a window frame meets the wall. Seal these with caulk or weatherstripping.
Then reduce what’s drawing them inside in the first place. Ants forage for food and water, so clean up crumbs and spills promptly, store food in sealed containers, and fix any leaky pipes or faucets. Outside your home, keep mulch, leaf litter, and vegetation several inches away from your foundation. Branches or shrubs touching the building act as bridges for ants to walk right in. Trim them back.
If ants in your yard are farming aphids or scale insects on your plants (they eat the sugary honeydew these pests produce), managing those plant pests will reduce the ant population nearby. Sticky barriers wrapped around tree trunks can also prevent ants from climbing into fruit trees and garden plants.
When Carpenter Ants Are the Problem
Most household ants are a nuisance. Carpenter ants are a structural concern. They don’t eat wood, but they excavate it to build their nests, hollowing out damp or decaying wood inside walls, floors, and framing. The telltale sign is small piles of coarse, sawdust-like shavings accumulating below a hole in the wood, sometimes mixed with bits of dead insects.
Carpenter ant colonies typically have a main colony outdoors (near a moisture source) and one or more satellite colonies indoors. The queen stays in the parent colony, which means killing the ants you see inside may not touch the reproductive heart of the colony. Baiting still works, but locating and treating the parent nest is often necessary for complete elimination.
Because carpenter ants nest inside structural wood and their colonies can be spread across multiple locations, they’re one of the cases where professional pest control is worth the investment. Professionals have access to dust formulations and injectable treatments that homeowners typically can’t buy, and they can trace satellite colonies back to the main nest. If you’re finding sawdust piles, hearing faint rustling inside walls, or noticing winged ants emerging indoors in spring, the colony is well-established and professional treatment will save you time and prevent further structural damage.