The most effective way to get rid of ants is with bait, not spray. Baits work slowly on purpose: foraging ants carry the poison back to the colony, where it spreads to the queen and the rest of the nest. Sprays kill the ants you can see but leave thousands more alive underground. If you want lasting results, your strategy needs to target the colony itself.
Why Bait Works Better Than Spray
When you see a line of ants crossing your kitchen counter, those are foragers. They represent a tiny fraction of the colony, which can number in the tens or hundreds of thousands. Killing foragers with contact spray feels satisfying, but the colony simply sends more. Worse, some sprays leave a chemical residue that repels ants away from the areas you’ve treated, pushing them to find new entry points instead of eliminating them.
Bait takes a different approach. It’s designed to be attractive enough that ants feed on it and bring it back to share with nestmates, including the queen. Once the queen dies, the colony collapses. An individual ant typically dies within 48 hours of eating bait, but full colony elimination takes longer: small infestations often clear up in 24 to 48 hours, while large or multiple colonies can take 2 to 4 weeks.
During those first few days, you’ll actually see more ants around the bait. That’s a good sign. It means foragers are recruiting others to the food source, which speeds up the process. Resist the urge to spray them or wipe them away.
Choosing the Right Bait for Your Ants
Not all ants want the same food, and using the wrong bait is the most common reason people think baiting doesn’t work. Different species have different preferences, and those preferences can shift with the season.
- Sweet baits work best for Argentine ants (the small, dull-brown ants that form long trails) and are effective year-round. Carpenter ants also prefer sweets.
- Protein or grease baits are better for pavement ants (dark brown, often nesting along sidewalks and foundations), Pharaoh ants, and thief ants. Argentine ants will also go for protein baits in the spring.
- Oil-based baits are the go-to for fire ants.
If you’re not sure what species you have, put out a small dab of something sweet (like honey) and a small dab of something greasy (like peanut butter) near the ant trail. Whichever one they swarm tells you what type of bait to buy. Commercial liquid and gel baits with slow-acting ingredients are widely available at hardware stores and work well for most household species.
A Simple DIY Boric Acid Bait
You can make an effective liquid ant bait at home using boric acid powder, which is inexpensive and available at most pharmacies and hardware stores. The key is getting the concentration right. Too much boric acid kills ants before they make it back to the colony. Too little won’t kill them at all.
A well-tested recipe from the University of Hawaiʻi uses 1 teaspoon of boric acid powder mixed with 3 tablespoons of white sugar, dissolved in warm distilled or bottled water (filled to the 1¾ cup mark). Stir until everything dissolves completely. Soak cotton balls in the solution and place them near ant trails, or use shallow containers like jar lids. Refresh the bait every few days so it doesn’t dry out.
This low concentration lets ants feed and survive long enough to carry the solution home. Place baits along the edges of counters, near entry points, and anywhere you’ve seen activity. Don’t clean up the ant trails with soap or vinegar right away, because those chemical trails are what lead other ants to your bait.
Safety Around Kids and Pets
Boric acid is relatively low in toxicity for adults, but it poses real risks for children and animals. Estimated lethal doses for infants are under 5 grams, and even small ingestions can cause vomiting, diarrhea, and irritability. Dogs may be more sensitive than other animals, and young or elderly pets face higher risk. Symptoms of ingestion, including excessive drooling, vomiting, fever, and diarrhea, typically appear within 2 hours.
If you have small children or pets, place bait stations in areas they can’t reach: behind appliances, inside cabinets, or in enclosed commercial bait stations that ants can enter but small fingers and paws cannot. Commercial pre-filled bait stations are generally safer for households with kids or animals than open cotton balls soaked in homemade solution.
Natural Repellents and Their Limits
Essential oils can disrupt the scent trails ants use to navigate, making them useful as a short-term deterrent. Peppermint oil is the most popular option because its menthol content is particularly irritating to ants. Cinnamon oil (high in cinnamaldehyde), eucalyptus oil, tea tree oil, and lemon oil (which contains citral and limonene) also repel ants on contact.
To use them, mix 10 to 15 drops of essential oil with water in a spray bottle and apply along windowsills, doorframes, and wherever you see ants entering. You can also soak cotton balls and tuck them into gaps.
The catch: these oils repel ants but don’t kill colonies. They’re best used as a complement to baiting, not a replacement. Spray essential oils around areas you want to keep ant-free (like food prep surfaces) while placing bait stations in areas where you want ants to keep coming (so they carry poison home). Used together, you’re steering ants away from your food and toward the bait.
Cutting Off Entry and Food Sources
Baiting handles the colony. Prevention keeps new colonies from moving in. Ants are scouting your home because they found food, water, or both. Removing those attractants makes your house less interesting to nearby colonies.
Clean up crumbs and spills immediately, especially sugary ones. Store ripe fruit in the refrigerator. Keep pet food bowls clean between meals, or place them in shallow dishes of water to create a moat. Take out garbage regularly and use bins with tight lids. Fix leaky faucets and pipes, since moisture draws ants just as much as food does.
For entry points, seal cracks and gaps around windows, doors, pipes, and where utility lines enter your home. Caulk is cheap and effective. Trim tree branches and shrubs that touch your house, because ants use vegetation as a bridge to reach upper floors and rooflines.
When You’re Dealing With Carpenter Ants
Most household ants are a nuisance. Carpenter ants can become a structural problem. These are noticeably large (up to half an inch), often black or red-and-black, and they hollow out wood to build nests. They don’t eat the wood like termites, but over time they can cause real damage to door frames, window frames, and wall voids.
A telltale sign is small piles of sawdust-like material (called frass) near wooden structures. Carpenter ants typically nest in tree stumps, firewood, fence posts, and similar outdoor wood, but they’ll move into your home if they find damp or softened wood to excavate.
Sweet baits can work for carpenter ants, but because their nests are often inside walls or structural wood, locating and treating the nest directly is usually necessary. If you’re finding frass or suspect wood damage, this is the situation where professional pest control earns its cost. The underlying moisture problem that attracted them also needs to be fixed, or they’ll return.
A Practical Game Plan
For a typical kitchen ant invasion, here’s the sequence that works: first, figure out what the ants are eating by testing sweet and greasy baits. Place the preferred bait along their trails and near entry points. Leave the trails undisturbed for at least a week so foragers keep recruiting. After activity drops, clean all surfaces thoroughly with soapy water to erase remaining scent trails. Seal entry points with caulk. Use essential oil sprays on surfaces you want to keep ant-free going forward.
If you’re still seeing heavy activity after 2 to 4 weeks of consistent baiting, you may be dealing with multiple colonies, a species that doesn’t respond to the bait type you’re using, or a colony nesting inside your walls. Switching bait types is worth trying before calling in professional help.