An anti-parasiticidal composition presented as a topical “pour-on” product for treating animals infected by parasites which are known to be susceptible to salicylanilides, especially closantel, alone or together with at least one other anti parasitic compound of the avermectin or milbemycin type and offers enhanced bioavailability of the salicylanilide by provision of a delivery system comprising at least 20% (v/v) of one or more alcohols, and optionally including a polymeric moiety selected from the group consisting of polyvinylpyrrolidone (PVP), polyoxypropylene/polyoxyethylene block copolymers (poloxamer), and polyethylene glycols (PEG), thereby improving the bioavailability of e.g. closantel (as assessed with respect to blood plasma levels of closantel).
