There are a number of commercial poisons on the market that can kill fleas. Unfortunately, they can be highly toxic to the pets that come into contact with them. Boric acid is less toxic than most of these poisons and can be extremely effective against fleas.
Use boric acid to kill the fleas that live in the carpet. When pets are around, fleas may hide in carpet and jump onto pets whenever they need a meal. They may also be hatching their young there. Boric acid powder can be sprinkled around the carpet in every room. It will then need to be brushed into the carpet to get it closer to the floor. If boric acid sits on the surface, fleas may still be able to live beneath it. Use a broom to sweep it deeper into the carpet.
Sprinkle small amounts on surfaces where fleas have been seen. This may include bare floors, stairs or furniture. The amount of boric acid that is applied should be thin enough so that the fleas won’t avoid the area. They need to move through the boric acid and get it on their bodies in order for it to work. A light sprinkling shouldn’t be noticed by them but will poison them as it works its way into their systems.
Apply larger amounts of boric acid across thresholds that you don’t want fleas to cross. This can be helpful in keeping the infestation confined to one or two rooms. A thick trail of powder placed in doorways can make it much easier to treat the rooms that are affected and to keep the rest of the home from needing treatment.