The efficacy and toxicity of 1, 4-Bis-trichlor-methyl-benzol were examined in the animal infections(rat, rabbit and mouse) of Clonorchis sinensis. The effective dosages to kill the worm in bile ducts were 1 x 150 mg/kg in rat and 5 x 150 mg/kg in rabbit. During 48 to 72 hours after the administration of the drug, the inactive posteriorly swollen worms and variously degenerated worms were observed from liver ducts, gallbladder and intestine of the experimental animals. In gall bladder of rabbits, a plenty of fragments of the worms and clewed mass of eggs were confirmed under microscope. The E.P.G. was not decreased to zero in 3 weeks observation after the administraiton of the drug except rabbit No. 9 which was treated with the dose of 5 x 250 mg/kg. Minimal congestion and mild cloudy swelling of liver were observed in the groups of mice which were given 5 x 150 kg and 3 x 500mg/kg of the drug respectively. The body weight of experimental animals showed no evidence of changes.
