Vinegar kills fleas. Distilled white vinegar as well as apple cider vinegar are demonstrated effective at killing fleas on dogs and cats. One method is to add vinegar to a pet's drinking water.
In the case of a dog, a teaspoon of vinegar is added to a quart of water for every 40 pounds the animal weighs. In dealing with fleas on a cat, about a half a teaspoon is added to the same amount of water. Vinegar or either type is suitable for application directly to an animals fur as a means of ridding the pet of fleas. The dog or cat needs to be confined and monitored after the application. Once the vinegar dries, the coat is combed and the animal bathed.