Light yellow stool color may be due to bile duct obstruction, liver lesions and other diseases. Bile is involved in the formation of stool color, and when bile is normally secreted, the stool will be normal yellow or yellowish brown. If the bile cannot be excreted into the intestines due to biliary obstruction, the stools will become light yellow because of the low bile. In addition, if there is a disease in the liver that interferes with the normal secretion of bile, the flow of bile into the intestines will also decrease, so the stools will be light yellow in color. The above mentioned are only some of the causes of light yellow stool, of course, there will be other causative factors. It is advisable to go to the hospital as soon as possible to have a thorough examination to determine the cause of the problem.