Which food kills cockroaches?

Several foods and substances mixed with food can kill cockroaches when ingested because they disrupt digestion, dehydrate them, or act as slow-acting toxins that roaches carry back to colonies, though effectiveness varies and commercial baits are more reliable than homemade mixtures. The most effective food-based killer is boric acid or borax mixed with sugar or flour, which is low toxicity to humans but lethal to roaches, as roaches eat the sweet mixture and ingest boric acid that damages gut and causes dehydration, and when used in gel baits containing fipronil or hydramethylnon it kills entire colonies within days to weeks because roaches carry it back through feces. Other foods that can kill include baking soda mixed with sugar, claiming to cause gas buildup, though evidence is limited and less effective. Diatomaceous earth mixed with food attractants kills by dehydrating roaches when they walk through it. Some people use flour mixed with plaster of Paris which hardens inside gut. However, foods that kill roaches most reliably are commercial gel baits formulated with attractive food bases plus insecticides like fipronil, indoxacarb, or abamectin such as Advion, Maxforce, and Vendetta, which are highly attractive to German cockroaches and American cockroaches and designed to be eaten and shared through coprophagy. Home remedies like cornmeal or grits claiming to swell are largely ineffective. For safety, keep boric acid baits away from children and pets, place in cracks and under appliances, combine with sanitation by storing other foods sealed so roaches are forced to eat poisonous bait, rather than relying solely on foods that kill.