Schistosomiasis mansoni and japonica, helminth infections involving the livers of 100 million people, are among the 'great neglected diseases of mankind' on the basis both of their prevalence and the relative lack of interest shown in them by clinicians and biomedical investigators. Schistosomiasis is not only an interesting disease in itself but has the added advantage of providing unique human and animal models of hepatic pathophysiology, immunopathogenesis, and collagen metabolism.