Sentinel Spectrum Chews is a chewable, bacon-flavored soft chew administered once a month to protect your dog from the threat of potentially deadly heartworm disease, for prevention and control of flea populations, and it also controls and treats against roundworms and hookworms and whipworms and tapeworms in dogs when given every month.Dogs six months of age and older should be tested for heartworm disease prior to being put on a preventive program and tested annually thereafter.