Sentinel is an oral tablet for the prevention and control of flea populations the prevention of heartworm disease and the treatment and control of roundworms hookworms and whipworms in dogsActive ingredients are Milbemycin oxime a heartworm and parasite preventative and Lufenuron an insect growth regulator Female fleas feeding on treated animals will produce eggs that cannot hatch The interruption of the flea life cycle results in effective long term flea control on the pet as well as in the environment Generally Sentinel is well tolerated by dogs of all ages and breeds including Collie breeds and other herding animals Sentinel should be given with a meal Consult your veterinarian for a recommendation on heartworm and flea prevention forOther products from PetCareRx