Vetsupply: Credelio for Dogs is a monthly oral chewable tablet for the treatment and prevention of flea infestations. It also treats and controls paralysis ticks on dogs and puppies. The clinically proven formula kills 100% fleas within 2 hours of administration. Credelio shows the efficacy for one full month against paralysis ticks, brown ticks and bush ticks. The oral formula starts killing fleas and ticks within 4 hours.