In particular this invention provides for spot-on compositions for thetreatment or prophylaxis of parasite infestations in mammals or birds whichcomprise: (1) a composition comprising (A) an effective amount of a 1-.rho.henylpyrazole derivative and (B) an effective amount of emamectin,latidectin or lepimectin (2) an acceptable liquid carrier vehicle and (3)optionally, a crystallization inhibitor. The invention also provides for amethod of treating parasitic infestations or for the prophylaxis of parasiteinfestations in mammals or birds which comprises topically applying to saidmammal treating parasitic infestations or for the prophylaxis of parasiteinfestations in mammals or birds which comprises topically applying to saidmammal or bird an effective amount of a composition according to the presentinvention.
