Boric Acid Is (Mostly) Safe as a Pest Control

Ben Kissam
Written by Ben Kissam
Updated February 14, 2022
Bottle of Boric acid, H3BO3 with Properties information and its chemical hazard warning symbols, Inhalation hazard symbol
Photo: mewaji / Adobe Stock

Boric acid sends (some) pesky critters packing

Get quotes from up to 3 pros!
Enter a zip below and get matched to top-rated pros near you.

If you’re dealing with a pest control issue, you’ve probably been searching high and low for a solution—but, in this case, the solution is boron. Boric acid, to be specific. When used in limited amounts, it can rid your home of a handful of critters.

Boric acid is often mentioned as an alternative to some harsher chemicals. But since it's considered toxic to humans, many wonder, is it safe to use in your home for pest control? Here's what you should know.

What Is Boric Acid?

Boric acid is a chemical made from borate, which occurs naturally in soil, water, and plants. It's most commonly sold as a product called Borax, which is available at major home improvement stores and some grocery stores.

Borax is considered to be low-toxic, but also not a completely "green" chemical by scientists. However, it is poisonous for humans and pets to ingest in large quantities, meaning you should educate yourself and use it carefully when removing pests from your home.

What Is Boric Acid Used For?

Boric acid can be used for many things, including:

  • As a low-chemical pest control substance

  • To balance a pool's pH levels 

  • As a treatment for ear infections

  • To cure chronic foot odor

  • To remove tough stains from clothes

*Remember, although it's natural, boric acid is toxic to humans. You should only use it as directed by a professional.

Is Boric Acid Safe to Use for Pest Control?

You need to be careful when using boric acid for pest control. Used properly, though, boric acid is considered safe. (It is worth noting, however, that boric acid is banned in the UK even for pest control purposes.)

Boric acid is not as strong as some chemicals used for pest control. Some see it as a more natural way to get rid of pests and a better alternative to using harsh chemicals.

Pest control companies make boric acid tablets you can leave around your home. It's also easy to mix Borax, flour, and water into small balls yourself and put them in areas where cockroaches, rodents, or flies are common.

If you have small children or pets at home, you should only put boric acid (whether bought at the store or made at home) in places where they cannot reach it.

Signs and Symptoms of Boric Acid Exposure

When ingested or inhaled in large quantities, boric acid could lead to:

  • Skin or eye irritation

  • Coughing

  • Nose bleeds

  • Diarrhea or vomit

Infants, who are more prone to boric acid toxicity, can suffer permanent nervous system damage from ingesting boric acid.

Seek medical attention immediately if you accidentally ingest boric acid.

Is Boric Acid Effective for Killing Pests?

Boric acid will definitely rid your home of some insects and pests. However, depending on the type of infestation you have, it might not do the trick.

For example, boric acid does not kill:

  • Ticks

  • Bed bugs

  • Lice

  • Spiders

  • Beetles

  • Flies

  • Fleas 

  • Moths

You may need more potent chemicals or different methods to extract these pests from your home, which could be a good reason to hire a pest control company to help.

How to Use Boric Acid for Pest Control

Follow these three steps to get your infestation under control. (Number two may look different depending on what's in your home.)

1. Purchase (or Make) Boric Acid Tablets

Decide whether to purchase tablets from the store or make your own at home. Depending on the level of infestation, you may need more than one box.

For the homemade option, you only need 1 teaspoon of boric acid per liter of water. Mix with flour and break into small pieces.

2. Research Your Infestation

Boric acid can be an effective remedy against cockroaches, rats, and flies. But there are specific things you need to know about each type of pest control.

For cockroaches, you'll only need to distribute tablets where you think they're living. It might also help to add some sugar to your homemade boric acid tablets to help attract insects.

Killing rats with boric acid can be trickier. Some scientists believe it can be ineffective for getting rid of rats unless they ingest it in large quantities, so you may need to leave many tablets scattered around the house. You also have to worry about shutting off access to areas where the rats may go after they eat the tablets.

For flies, attach boric acid tablets to fly strips or put boric acid in a cup of vinegar.

3. Clean Thoroughly

It's a good idea to clean the areas where you've left tablets or boric acid balls after you're done. Give it two to three days to see the results. 

Adult flies usually die when exposed to boric acid, but their larvae often survive. So it might be a good idea to put more boric acid balls out to kill off the now-hatched larva.

Talk to a local cockroach exterminator to get your pest control issues sorted out.

Need professional help with your project?
Get quotes from top-rated pros.