8 rabbits were infected percutaneously with the cercariae of Schistosoma japonicum. After hepatic fibrosis had developed in these rabbits 4 months after infection, 4 out of the 8 infected rabbits were given colchicine orally at a dosage of 40 micrograms/kg per day for 7 weeks. Another uninfected rabbits were used as controls. The therapeutic effects of colchicine on hepatic fibrosis were studied by transmission electron microscopy and morphometry, in which the area of collagen microfibrils in the space of disse and liver cells was measured. The results showed that colchicine relieved ultrastructural injury of liver cells and reduced the number of active fibroblasts and collagen microfibrils. The area of collagen microfibrils measured in the liver of the infected rabbits and colchicine-treated rabbits accounted for 42.5% and 0.2%, respectively (P less than 0.01), suggesting that colchicine has therapeutic effect against schistosomal liver fibrosis.