Can Boric Acid Kill Ants Instantly? Learn How to Use it Safely

After seeing armies of ants in my attic, I found several online boric acid bug-killing recipes. I immediately thought, “Does boric acid kill ants?” It does, but important details must be followed to kill ants with this chemical. Relax, because over here at, we're keen to details.

Are you afraid of harsh pesticides? Effective ant-killing methods like the boric acid solutions are at one percent, making them less toxic to humans and animals. Do you want to make your own bug killer or buy it ready-made? Both options are possible.

Can Boric Acid Really Kill These Ants?

According to the National Pesticide Information Center, boric acid wrecks an ant’s stomach. It also hinders the ant’s nervous system. An irritant, boric acid also harms an insect’s exoskeleton. If you or I consumed huge quantities of boric acid, a product mined from borax, we would die, too.

The key to ant-killing boric acid is two-fold: it is mixed with bait that attracts bugs, and only one percent or less of the bait contains boric acid. The University of California-Davis’ Integrated Pest Management website explains that insect baits are effective because of the ant’s social nature.

Worker ants are attracted to the bait. They carry bits of the bait back to the insect nest, urging other workers to get more bait. At the nest, the boric acid laden bait is transferred between mouths of all insects in the nest, effectively infecting and killing every bug, all larvae, and the queen.

A Slow Process is the Best Process

Killing bugs in this fashion must be slow, since a worker ant killed outside of the nest never infects other insects. That is why you need bait containing only one percent boric acid. It gives worker ants enough time to move the bait to the nest before getting sick and dying.

Ants need to like boric acid insect bait in order to take it back to the nest. Drs. John F. Klotz and David P. Williams proved in their 1996 paper that too much chemicals will either repel ants or kill off a colony too fast, making the survivors move the nest to a new location.

This slow killing nature of boric acid ant bait means you might see bugs for several days. Killing a large sugar ant colony once took me three months. Boric acid kills ants and can harm animals, but at a low level, it’s considered by Clemson University scientists to be a less toxic insecticide.

Where to Buy Ant Killing Boric Acid Online

You can purchase inexpensive and effective ant insecticides containing the chemical as their main ingredient online. A popular choice is Terro® Ant Killer II, which is applied as liquid drops on cardboard squares. You need to reapply this insect bait daily in order to gain an effective kill.

If working with drops of liquid seems messy to you, another option is Terro® Ant Killer Liquid Ant Baits, which are prefilled bait stations. Similar stations are available for outdoor use with Terro® Outdoor Liquid Ant Baits.

You won’t see ants dying instantly when you use this product, due to the slow nature of how the formulated chemical works. Don’t be surprised if your new bait looks like you rang the insect dinner bell. Following directions is important. Terro’s YouTube videos gives you tips on using their product.

You can find other brands of bug killing insecticide that contain boric acid. Check product packaging to ensure you’re getting the right product. The active ingredient should contain the words “boric” or “borate.” The boric acid should be in the amount of one percent by weight.

How to Make Your Own Boric Acid Ant Killer at Home

If you are a do-it-yourself kind of person, making your own boric acid ant killer or any other insect killer is possible. Just be sure to follow a definitive guide.  Be aware that boric acid is toxic to plants and animals, so care is essential. Keep boric acid off kitchen countertops. Since boric acid can sterilize soil, don’t use or mix it around plants.

Precision is also essential when you make chemical ant bait, because too much will drive insects away instead of killing them. Too little boric acid in your bug bait recipe will only tickle them. Relatively inexpensive boric acid is available online.


An easy boric acid ant bait recipe involves first making sugar water by mixing eight teaspoons of sugar into a cup of water. Then add ½ teaspoon of boric acid to your sugar water. This combination gives you the one percent boric acid ratio important for effectively killing ants.


Boric acid will kill ants. But, you won’t see bugs falling down like the bad guys in an old Clint Eastwood spaghetti western movie. Instead, chemical ant killer takes time for insects to pass it to one another and infect the whole bug colony.

And for more info on how to rid your home of these little insects, go straight to this link :​

If you see ants in your attic, like I did, do the following:

  • Either buy an ant insecticide containing one percent boric acid, such as Terro® Ant Killer II;
  • Or, make your own boric acid ant bait, using precise measurements.
  • Finally, meticulously use your bait for several days and expect the process to take time.

I know this was "wow", right? Remember, if you happen to have mouse in your attic, follow our recommended mouse trap bait to use, and be sure to read up more tricks on this blog; not even a pigeon on your roof can escape our method.

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