Lufenuron, the chitin synthesis inhibitor (Program, Novartis-Switzerland) was given orally at doses of 10-mg/kg b/w to dogs and 30-mg/kg b/w to cats every four weeks (monthly) for the treatment of experimental flea infestations. Three to four weeks after the last infestation, Lufenuron had effectively controlled the Ct. felis infestation of dogs and cats as the drug prevented the development of the offspring of adult female fleas feeding on animals. Flea populations were absent or very low and remained so until the end of the study, 91 days after the first treatment.