Fecal color originates in the gall pigment "bilirubin". Bilirubin is a derivative of the hemoglobin’s metabolism and is excreted through gall fluid into the intestines. In the intestines, the bilirubin is transformed into a sterkobilin that gives feces its yellow-brown color. Without sterkobilin, the feces become white. White feces could be a very serious sign of an internal disorder...you can visit your GP immediately! Bilirubin and urobilinogen in the blood and urine will be examined.