The researchers gave each of these patients a combination of the drugs azathioprine, prednisolone, and ursodeoxycholic acid and watched them for between 3 and 81 months (41 months on average). The patients had examinations, blood tests, samples of liver tissue taken (biopsies) to be examined under a microscope, and special tests called endoscopic retrograde cholangiography (ERCP). The ERC involves putting a tube down someone's mouth into their intestinal tract and squirting dye into the bile ducts so the degree of blockage will show up on special x-rays.