Objective To evaluate the relationship between endothelin (ET) in bile and peripheral blood with systemic and hepatobiliary injury in patients with acute cholangitis of severe type (ACST). Methods ET, ALT and total bilirubin in bile and peripheral veinous blood of 25 patients with acute cholangitis of severe type (ACST) were detected during operation, one week and two weeks after operation. Results The contents of ET, ALT and total bilirubin were significantly lower on 7-day and 14-day after operations as compared with that during operations (Ｐ＜0.05 and Ｐ＜0.01). The concentration of ET in peripheral veinous blood paralleled with that in bile. Conclusion This suggests that ET is tightly related with the pathologic process of ACST. So, in patients with ACST, the dynamic measurement of ET in peripheral veinous blood can be an index for judging the degree of pathological damage either to the hepatobiliary or systemic systems.