White stool isn't normal and should be evaluated promptly by a doctor. White or clay-like 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 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.
Often the problem occurs in the tube (duct) that delivers the bile to the small intestine. This tube can be squeezed shut or blocked — for example, by a tumor or a gallstone — which prevents the bile from entering the small intestine. You may also experience abdominal pain, fever, nausea, itching and jaundice (yellowing of the skin and eyes). Some babies are born with constricted bile ducts.
Liver diseases, such as hepatitis and cirrhosis, also can sometimes cause white stool. Barium, a white substance used for X-rays of the digestive tract and certain medications that contain aluminum hydroxide, for example antacids, can also turn the stool white.