Frontline Spot On Plus for Cats completely breaks the flea life cycle and controls tick and chewing lice infestations. Research demonstrates the FRONTLINE PLUS kills adult fleas, flea eggs, and flea larvae for up to six weeks. FRONTLINE PLUS kills ticks for at least one month. A once monthly application is recommended where tick control is needed. Although FRONTLINE PLUS can control fleas for up to six weeks, if there is a high risk of infestation or if the pet has fleas which may cause flea allergy dermatitis, a once monthly application may be needed.