Abstract
Partial obstruction of the common bile duct was produced in rats by tightly tying a 0·5 mm stainless steel rod to the proximal common bile duct. The rod was then removed from the ligature leaving a constriction around the duct. Within 2 weeks the bile duct proximal to the partial obstruction was markedly dilated. Liver histology was notable for marked proliferation of the interlobular bile ductules and minimal cholangitis, changes which are characteristic of partial obstruction.