To observe triclabendazole effect on Paragonimus skrjabini in experimentally infected rats,and to develop a new drug for treating paragonimiasis.Metacercariae of Paragonimus skrjabini were isolated from crabs (Sinopotamon) collected from endemic area. Wistar rats were infected intraperitoneally. One and two months after infection, they were treated with triclabendazole at the dosage of 300 mg.kg(-1).2 d(-1), 450 mg.kg(-1).3 d(-1) and 600 mg.kg(-1).3 d(-1) respectively. Five patients with Paragonimus skrjabini were treated, with Triclabendazole dosage of 10 mg/kg bid x 3 days.The worm reduction rates were 50.3%, 80.8% and 86.7% respectively one month after completion of treatment. Dead worms of sesame size recovered from muscles, liver, abdominal cavity, chest cavity and lung were greatly diminished in size and weight in comparison with that of the control group. Many large (about 1 cm) black-colored distended worm cysts were found in the lungs of the control rats. Usually there were two adult worms pairs with numerous eggs in each worm cyst. Most worm cysts in the treated groups of rats were changed into hemorrhagic-necrotic patches. All five patients were cured.Triclabendazole was highly active against Paragonimus skrjabini in rats experimentally infected and patients.