The invention provides a method of treatment of a human subject to combat infestation by multicellular ectoparasites with exoskeletons, in particular head lice, which method comprises topically applying to said subject a first and a second pediculicide, said first pediculicide being a carbamate or organophosphate pediculicide and said second pediculicide being a pyrethroid or pyrethrin pediculicide, characterized in that said second pediculicide is applied between 15 minutes and 12 hours after the application of said first pediculicide.