[Etiology of cholelithiasis].

The incidence of gallstone has been gradually increased in the last few decades in Japan and the recent study revealed that approximately 15% of the autopsy cases had biliary stones. In the last 25 year interval, the nature of gallstones was greatly changed. In detail, the incidences of cholesterol gallstone and black stone were increased from 46.7% to 66.9% and from 0.8% to 12.1%, respectively, whereas that of calcium bilirubinate stone was decreased from 41.5% to 21.0% of the whole cholelithiasis cases. The factors influencing these changes were probably due to recent increase of fat diet intake and decrease of ascariasis by improvement of environmental hygiene. However, the factors that caused the change in black stone has not been defined.