The authors surveyed 36 cases of acute severe cholangitis (AOST) treated from 1981 to 1990. The results showed that ACST would consist of acute obstructal suppurative cholangitis (AOSC) and acute suppurative cholangitis(ASC), depending on the obstructal degrees of biliary tract. 27 cases with AOSC had a high mortality(12/27) with the rapid development of septic shock; however, all the cases(9/9) with ASC survived at all with the slower develpment. of the other hand an experimental model of acute cholangitis was conducted in the Japanese big ear white rabbits in accordance with the various degrees of biliary obstruction. The results confirmed that the mean artial blood pressure (MAP) yielded a reduction of 7.6kpa(55mmHG) at complete obstructal group at 48 hr, it was much higher than that of 4kpa at partial obstructal group (P<0.01). The authors suggests that the obstructal degree of biliary tract is an important factor affecting the features development of ACST. and yet, it was observed that a significant fall of MAP(P<0.05) did not inversely paralled with the increase of blood endoroxim(p<0.05). The result indicated the existence of other factors making MAP decrease.