"SENTINEL?Flavor Tabs?can protect against five nasty parasites that threaten your dog include fleas, heartworms, hookworms, roundworms and whipworms. SENTINEL Flavor Tabs are the only monthly oral preventive that guards against heartworms (Dirofilaria immitis) and fleas as well as adult roundworms (Toxascaris leonina), adult hookworms (Ancylostoma caninum) and whipworms (Trichuris vulpis). And SENTINEL Flavor Tabs are so convenient. Just one tablet, once a month with a meal, gives your dog the most complete protection possible. As with other heartworm preventives, dogs must be tested for heartworm prior to using SENTINEL Flavor Tabs. Each packet has a 6-month supply (6 tablets). A prescription is required for this product. Click here for details"