For treating heavy flea infestation in canines, Capstar is an active formula. This quick action tab works well in killing adult fleas. Within 30 mins of administration, Capstar starts destroying fleas and within a few hours, it removes 98-100% fleas. Treatment with Capstar poses no danger to pregnant and nursing bitches. As safe to use at 4 weeks of age of puppies and above, it is suitable for all breeds of dogs.