Yellow and/or pale stools
Stool starts out green , then turns bright yellow as it goes through the digestive tract. It is bile and bacteria that finally turn it brown.
Yellow or green stools can indicate stool is passing through the digestive tract too rapidly not giving it a chance to change colour. Bright yellow stools can also indicate not enough bile / bilary obstruction.
Yellow stools may be also due to certain medications or diet supliments.
Malabsorption problems can cause undigested fat in the stool (steatorrhea) which is characterized by foul smelling, light yellow to gray, greasy or frothy stools. This may also be caused by low bile output.
Pale stools, putty or clay colored stools may be seen in hepatitis, gallbladder disorders, or malabsorption conditions, which obstruction to bile flow out of the liver.
Bile salts in the stool excreted by the liver give it a normal brown color.
Possible causes for clay colored stool result from problems in the biliary system (the drainage system of the gallbladder, liver, and pancreas):