Trifexis is a monthly chewable tablet for dogs that kills fleas, prevents heartworm disease and treats and controls adult hookworm, roundworm and whipworm infections. Trifexis combines two trusted active ingredients to provide protection for your dog against these dangerous parasites. Trifexis is beef-flavored, so you can offer it as a treat. Trifexis is given orally so you don't have to isolate your dog from other pets or children.