Global menu

The Green pages

Borax and boric acid

Borax or boric acid may be used to control ants
Photo: Insectarium de Montréal (Claude Pilon)
Ant, Québec, Canada.

The information below is intended only as a guide.
Always read product labels carefully.

Product description

Borax and boric acid are derived from boron, a naturally occurring element in soil, rocks and water.

Pesticides with borax or boric acid as the active ingredient are used in the garden as insecticides. They are available in powder, liquid or trap form. Manufacturers often add such baits as sweet liquid or peanut butter.

Target pests

Products with borax or boric acid as the active ingredient may be used to control ants and earwigs.

NB: The product label lists the plants on which the pesticide may be used, along with the target organisms. 

How it works

Borax and boric acid act as stomach poisons when eaten by insects. Death occurs a few days later.

NB: Bait formulations rely on trophallaxis, the exchange of food among ants. After finding and eating the poisoned bait, ants take it back to the colony to share. The entire colony is affected after several days. Hence the importance of not crushing any ants that have visited the bait.


  • Powder formulations
    • Spread a thin layer of the powder along insects' routes (at the base of foundations and walls, along doorsills, etc.). Avoid damp or wet locations, because the powder is effective only when dry.
  • Bait formulations
    • Liquid: In the garden, apply along insect routes or near ant nests (some manufacturers recommend placing the insecticide on a piece of wax paper).
    • Traps: Place traps along insect routes or near ant nests. In most cases, you will need to punch holes in the trap. Never remove the lid.


The product may irritate the skin and eyes, so it is best to wear gloves, long sleeves and pants and goggles when applying it. It is best to wear a mask when applying a powder formulation, to avoid inhaling the pesticide.

Some products may contain peanut butter, and may be hazardous for people with allergies.

It is best not to apply it on windy or rainy days, to keep it from drifting or rinsing off.

Avoid applying powder or liquid formulations near plant roots. Borax and boric acid can cause plants to dry out and/or interfere with photosynthesis.

Do not use near any body of water or wetland, or dump any pesticide or rinse your equipment there, as this will contaminate the water. Never dump pesticides down sewers.

Keep out of reach of children.

Add this

Share this page