Abstract: Rabbits were infected with Schistosoma japonicum cercariae and the collagen content, collagenase activities in the liver and monoamine oxidase(MAO), α2-M in serum were examined post-infection. The results showed that 8 weeks post-infection (pi), the liver collagen content in infected rabbits was 23.14±5.23 (normal control value: 10.56±1.73 mg/g wet weight), and was 32.89±7.04 11 weeks p.i, 27.29±8.86 18 weeks p.i, but 28.34±11.95mg/g wet weight 14 weeks after pyquiton treatment. Collagenase activities were 32.99±7.34 (compared with normal group, P〈0.05), 16.88 ± 5.99, 11.13±3.35 (P〈0.05) and 14.30±5.41u, respectively. Serum MAO increased from the 4th week on but tended to return to normal after pyquiton treatment. A negative relationship was noticed between collagenese activities and collagen content (P〈0.01). It was suggested that the abnormal collagen metabolism was related to immunological reaction caused by granuloma formed by schistosome eggs and the increase in collagenase activities is an important factor in the catabolism of liver collagen.