White stool is not normal and should be evaluated promptly by a doctor. White stool is caused by a lack of bile, which may indicate a serious underlying problem.
Bile is a digestive fluid produced by the liver and stored in the gallbladder. Stool gets its normal brownish color from bile, which is excreted from the liver into the small intestine during the digestive process. If the liver doesn't produce bile or if bile is obstructed from leaving the liver, stool will be light colored or white.
Liver diseases, such as hepatitis and cirrhosis, can cause white stool. In some cases, the problem lies not in the liver but in the tube (duct) that delivers the bile to the intestines. This tube can be squeezed shut or blocked — for example, by a tumor or a gallstone — which prevents the bile from entering the intestines. Some babies are born with constricted bile ducts.