Sentinel Spectrum is a monthly oral preventive prescription that guards against heartworms, adult roundworms, adult hookworms, whipworms, and prevents the development of flea eggs. It protects your dog against heartworm disease and intestinal worms, all in a palatable, beef-flavored chewable. Sentinel Spectrum is indicated for use in dogs and puppies, four weeks of age and older, and two pounds body weight or greater.