Last Updated: July 2026 | Reviewed by The PCC Research Team
If you live in California, you are almost certainly battling the Argentine Ant. These aggressive, multi-queen super-colonies laugh at bug sprays. Spraying a trail of ants on your kitchen counter only kills the 1% of workers you can see; the remaining 99% hiding behind your walls will simply replace them tomorrow.
To permanently solve an ant infestation, you must use a slow-acting stomach poison. The workers will carry the poison back to the nest, feed it to the queens, and collapse the colony from the inside out. The most effective, inexpensive, and readily available stomach poison is Borax.
Materials Needed
- Borax (Found in the laundry aisle)
- White Sugar or Honey
- Peanut Butter or Cooking Oil
- Warm Water
- Cotton Balls
- Small bottle caps or wax paper
The “Too Strong” Mistake
The biggest mistake homeowners make is adding too much Borax to the mixture. If the bait is too toxic, the worker ant dies on your kitchen counter before she can walk back to the nest. A successful bait must keep the ant alive for 24 to 48 hours. You want a maximum of 1% to 5% active ingredient. Less is actually more.
Mix the “Sweet” Recipe
In the spring and summer, colonies are expanding rapidly and require carbohydrates (sugar) for energy. This is when sweet baits are highly effective.
- 1/2 Teaspoon of Borax
- 2 Tablespoons of White Sugar
- 1 Tablespoon of Warm Water
Stir the mixture thoroughly until the sugar and Borax completely dissolve into a thick syrup. Soak half of a cotton ball in the liquid. Place the soaked cotton ball on a piece of wax paper or inside a shallow bottle cap.
Mix the “Protein/Grease” Recipe
If you put down a sugar bait and the ants completely ignore it, do not panic. Depending on the life cycle of the colony, the queens may be demanding protein to produce eggs. You must offer them a fat-based alternative.
- 1/2 Teaspoon of Borax
- 2 Tablespoons of Creamy Peanut Butter (or Bacon Grease)
Mix the Borax thoroughly into the peanut butter. Place a pea-sized dollop of this mixture on a piece of wax paper right next to your sweet bait. By offering a “buffet” of both sugar and protein, you guarantee the ants will take the poison regardless of what the colony is craving today.
Strategic Placement
Do not place the bait randomly in the middle of the floor. Ants navigate using invisible pheromone trails. You must intercept their current path.
- Place the bottle caps directly in the path of an active ant trail.
- Place baits near entry points: window sills, under the kitchen sink, behind the toilet, and near exterior door frames.
- Safety Protocol: Borax has low toxicity, but it will upset the stomach of dogs and cats if eaten in large quantities. Ensure all baits are pushed deep under appliances or placed inside sealed plastic containers with small entry holes poked in the sides.
The “Do Not Disturb” Phase
This is the hardest step for most homeowners. Within a few hours of placing the bait, you will likely see a massive swarm of hundreds of ants covering the cotton ball. You must let them feed.
Do Not Spray The Swarm!
If you panic and spray the feeding ants with Raid or wipe them up with a sponge, you will ruin the entire process. You just killed the workers before they could deliver the poison to the queen. You must allow them to eat and return to the wall void unharmed. The swarm will usually vanish entirely on its own within 48 to 72 hours as the colony collapses.
Frequently Asked Questions
Dealing with Carpenter Ants?
While Borax works wonderfully for nuisance house ants, it will not stop Carpenter Ants from actively destroying the wood framing of your home. If you see large, black ants or sawdust near your baseboards, you need professional structural treatment.
Find a Licensed California Exterminator »