Oral Pill (Program , Capstar , Sentinel ) These products prevent flea eggs from hatching when administered orally to pets once a month at mealtime. Dogs are fed Program in tablet form, whereas cats are fed a liquid suspension mixed with their food. Different tablet sizes and suspension doses are prescribed according to the weight of the animal. When an adult female flea bites a Program treated dog or cat, the flea ingests the active ingredient (lufenuron) which then passes into her eggs and prevents them from hatching. A companion product, Sentinel™, contains both the flea control ingredient and heartworm medication all in one dosage. See Allivet's Flea and Tick chart to find which flea and tick product is best for your pet.