There is disclosed herein a composition for treating extracellular parasitic infections, the composition comprising one or more of the following combinations: at least one quinolone or fluoroquinolone together with at least one tetracycline, iodoquinol, an azole or imidazole； or at least two agents selected from the group consisting of iodoquinol, thiazolidones, tetracycline, nitroimidazoles, cotrimoxazole and diloxanide furoate.There is also disclosed herein a method for treating extracellular parasitic infections in a vertebrate in need of said treatment, wherein said treatment comprises administering to said vertebrate a therapeutically effective amount of (i) a composition comprising a quinolone or fluoroquinolone together with a pharmaceutically acceptable carrier or (ii) a composition of the invention or (iii) a combination of at least one quinolone or fluoroquinolone optionally together with at least one tetracycline, iodoquinol, an azole or imidazole； or (iv) a combination of at least two agents selected from the group consisting of iodoquinol, thiazolidones, tetracycline, nitroimidazoles, cotrimoxazole and diloxanide furoate.
