0chickchoc 9 years ago ReplyUpvoteBrewers yeast in the food works well. You can also dust animals with diatomaceous earth. This looks like dust and is sometimes used in pool filters. DE will also kill roaches and ants. It's totally nonpoisonous to pets and people and works equally well wet or dry. I dust my carpets with it to get rid of insects and use it outdoors for ants. Good luck.