Does Cornstarch Kill Ants? How it Works

Cornstarch kills adult ants because they cannot digest solid food. However, it will not eliminate ants at their larvae stage because they can digest it. Cornstarch alone does not have a sweet taste that can attract ants. You need to mix it with something sweet, like sugar.

Cornstarch is used to kill ants because it forms a thick solid layer in their stomach. Combine 2 tablespoons of cornstarch with 1 tablespoon of sugar and 15ml water. Then spread this mixture in their trails and let them eat.

Sugar will attract ants, and they will also eat the cornstarch that is mixed with it. The more they eat, the faster they die.

How to get rid of ants with cornstarch

How to kill ants using cornstarch

If you use cornstarch alone without mixing it with anything, make it a little bit wet. Ensure you clear anything that will attract the ants so they can starve. Here is how to get rid of ants using cornstarch:

  1. Put 1 cup of flour in a container
  2. Add 1/2 cup of sugar to attract the ants faster
  3. Pour 1/2 cup of water into the mixture to form a paste
  4. Spread the paste along their trail and in areas where they live

If you are dealing with a large number of ants out outside, simply spread the cornstarch over the ants. They will take this back to their colonies to feed the queen.

If the queen is no more, then it means they will not multiply and the ant population will be reduced. To make it even more effective, you can mix the cornflour with borax powder.

Cornstarch bait for ants: Mix 1 cup of cornstarch with 1/2 cup of borax and sugar, then spread it on their trail. They will carry the particles back to their nests. This is one of the fastest ways to get rid of ants because they will die in less than 30 minutes after eating the mixture.

How long does it take for cornstarch to kill ants?

Adult ants will die in less than 3 hours after taking solid cornstarch. This is because they can not eat or digest solid food. When eating any solid food, adult ants produce a juice that will convert the food into liquid before they digest it.

When using cornstarch against ants, mix it with water so that they digest it faster and easier. If you are clearing a big colony, it may take 1 day for you to start seeing some results.

Ants are always looking for food; if you want cornstarch to kill them fast, ensure that they have nothing to eat. If they eat the powder with an empty stomach, they will die in less than 3 hours.

What can you mix with cornstarch to kill ants?

To speed up the whole process, there are things that you can mix with cornstarch to kill ants. In most cases, you should go for toxic and sweet stuff that can work simultaneously.

You can mix cornstarch with sugar, borax, and baking soda. While borax and baking soda will kill the ants, sugar and cornstarch attract them. If you mix all those together, you shall have made one of the best homemade ant killers.

The idea here is to have the sweet stuff like sugar in low quantities and the toxic in the quantities. In this case, the baits should be equal to work best. In fact, this is one of the best and safe ways to kill those small ants in the house.

The idea here is that we are trying to kill the ants, not feed them. If you buy the baits in large quantities, you are losing the whole point. You will only be attracting the ants and keeping them away.

Does cornstarch repel or attract ants?

Cornstarch does not repel ants because it does not have any chemicals that will do so. In fact, it will attract ants because it is food, and they will eat and take some back to their nests for the rest to have a meal.

Cornstarch alone is enough to get rid of ants, and is also one of the best natural ways to kill ants. We only mix it with sweet things like sugar to make the process fast because corn will not attract the ants as fast as sugar will.

This is why in some cases, we also add borax and use cornstarch as an ant bait. An added advantage of this is that it can be used to eliminate ants indoors and outdoors.

If you have a grass plantation in your yard or compound and ants infest it, simply spread cornstarch powder all over the place and let the ants enjoy the meal. This will effectively control the population in a span of one week.

Cornstarch ants myth

One of the most common myths about ants and cornstarch is that ants can feed on cornstarch, increasing their population because they are attracted to it as a meal.

This is a myth because once they take it, it will solidify in their system, and they will die. They will take it thinking that it is a meal, but in the end, it will be deadly, and this can wipe out quite a significant number of them.

It is also a myth to say that ants cannot eat cornstarch alone because it is not sweet. Ants love cornstarch because it is made from the endosperm of corn grain. The endosperm contains natural sugar, and that is enough to attract ants because they will find it tasty.


  1. NCBI: Metabolism of sugars in the endosperm of developing seeds: Oxford University Press
  2. University of Florida: Insect pest traps: EDIS