The efficacy of a single dose of benzimidazole, drugs commonly used for the treatment of Ascaris and hookworm, was evaluated against one of the tiny-sized intestinal flukes, Haplorchis sp in the endemic area where mixed infections of roundworms and flatworms existed. At day 7 after treatment, albendazole (400 mg) induced 42.5% cure rate, mebendazole (500 mg) a cure rate of 32.4%, on the other hand, praziquantel (40 mg/kg) gave 94.6% cure rate and the placebo at 15.9%. At the single dose, benzimidazole could not completely expelled the haplorchid; but could reduce one third to two fifth of the infection, similar to the
drugs efficacy against Trichuris infection.

Keywords: Haplorchis sp, Treatment, Single dose, Albendazole, Mebendazole