The present invention relates to a veterinary or pharmaceutical composition comprising: (i) about 1-65% w/v of a pyrethroid, or a salt thereof, (ii) a macrocyclic lactone, or a salt thereof, (iii) at least one alkalizing agent, (iv) at least one non aqueous solvent, wherein the pH of the composition is comprised between about 6.5 and 8.5, when measured by adding 25% of water to an aliquot of said composition. The invention further relates to the use of such composition for preventing and/or treating parasites infestations.
