Possibly stool, and acceptably, come in a lot of shades of brown, and even black and green, but white stool is not normal and requires action, according to the gastroenterologist Dr. Picco in mayoclinic.com (see References).
If the stools are white means, according to Picco, which lacks the bile, which is digestive fluid produced by the liver and stored in the gallbladder. Lack of bile indicates a potential problem in the biliary tract or liver. Healthy stool is brown and gets the color of the bile that is excreted by the liver during the digestive process and enters the small intestine. If the liver does not produce bile or if it does but is impeded or obstructed bile at the exit of the liver, stool will be white.
Medications can turn your bowel movement in white, including anti-diarrheal drugs and large doses of Pepto-Bismol or Kaopectate. Some antifungal medications, antibiotics and antacids can also have this effect on the color of the feces.
Medical conditions that can cause the stool take a clear or white can include narrowing of the bile ducts, gallstones, tumors, cysts, errors of metabolism, a liver infection such as hepatitis or biliary cirrhosis, bowel congenital anomalies and bile duct.
The bile duct obstruction
An obstruction of the bile ducts can be caused by a number of conditions, including gallstones, inflammation of the bile ducts, injury gallbladder surgery, enlarged lymph nodes in the porta hepatis, cysts bile duct, tumors in the bile ducts and the pancreas or tumors that have spread to the biliary system. A person may be at risk of this happening if you have a weakened immune system, which can cause blockage by infections, injury to the abdomen, biliary cancer, biliary surgery, pancreatic cancer, pancreatitis or a history of gallstones, according nlm.nih.gov (see References).
Besides converting your stool in white, a bile duct blocked may cause jaundice and convert skin in yellow due to the accumulation of bilirubin in the blood.
If you have digestive problems, this may turn your stool in a pale color, according to Wrongdiagnosis.com (see References). The digestive system consists of a tube leading from the mouth to the rectum and housing the esophagus, stomach and intestines, as well as organs which are connected to the tube, including the liver and pancreas. If you have a duodenal incontinence, fecal, Whipple's disease, dysentery or esophageal achalasia, there is a possibility that feces may be pale in color.