Many people wonder – Does Diatomaceous Earth Kill Ants?

If you’re wondering does diatomaceous earth kill ants, the answer is – yes! Diatomaceous earth has been shown to be very effective at killing ants and other crawling insects. In fact, the Government of Canada suggests diatomaceous earth as an alternative to chemical pesticides when trying to kill ants. Food Chemical Codex Grade diatomaceous earth is not toxic to humans or pets and will remain effective as long as it is present and dry, as mentioned by Health Canada. (Please note: diatomaceous earth insecticides such as Last Crawl can be applied wet and left to dry. The product will be effective once dry. Therefore, as long as the product has not been washed or blown away, it can get wet and re-dry and will continue to be effective.)

Please be sure that the diatomaceous earth insecticide that you plan to use to kill ants is registered for this purpose. DE insecticides like Last Crawl are registered specifically for use against ants. As a result, they will have this stated on the label.

Check the label, when in doubt. An insecticide that has been properly registered should indicate which insects it is most useful against.

Last Crawl Insecticide Label

How does diatomaceous earth kill ants?

Ants and other crawling insects have a waxy outer layer on their bodies. The sharp microscopic particles that make up diatomaceous earth pierce through this layer and, as a result, cause the ant to die by disrupting its internal water balance. Consequently, the ant dehydrates and dies.

Ants must come in direct contact with the DE in order for it to be effective. Therefore, Last Crawl should be applied behind appliances, cabinets, along baseboards, along edges and underneath carpets, rugs and bed frames, when used indoors. Outdoors, light coat ant trails, door frames, entrance ways, foundations, patios, window frames, window sills, shrubs, flower beds, gardens etc. Similarly, for both indoors and out, it is important to pay careful attention to cracks, crevices, and other areas where insects may hide or crawl.


Last Crawl Diatomaceous Earth Insecticide can be mixed with an attractant. This will encourage ants and other insects to ingest it. Attractants can include cereal or nut powder, icing sugar, powdered soup mixes, powdered yeast, or other dry, powdered, food-grade attractants. Mix the attractant in at a rate of 25 – 50% in volume. Ingesting the DE will cause further dehydration by lacerating the digestive tract.

For a complete list of insects that diatomaceous earth is effective against check out – The Effectiveness of Diatomaceous Earth: Insect List