"Frontline Plus for Dogs Under 23-44 LB Frontline Plus for dogs and cats is a monthly flea preventative killing 98-100% of adult fleas on your cat or dog within 24 hours. Frontline Plus contains a special ingredient that kills flea eggs and larvae and keeps all stages of fleas from developing. Effective Flea and Tick Control . . . No Prescription Required! Guaranteed USA EPA approved. Over-The-Counter topical kills fleas and ticks in under 48 hours Protect against Lyme Disease! Easy to apply Frontline Plus contains an insect growth regulator, S-methoprene, which kills flea eggs and larvae. It's effective against all stages of the brown dog tick, the American dog tick, the lone star tick and the deer tick (the major carrier of Lyme disease)."