The normal color of a bowel movement is any shade of brown (usually medium brown), or brown/green. When yellow/pale stool appears, and there is no obvious reason due to consumed food, there might be anyone of the following disorders:
Diarrhea: Diarrhea is the most common reason in changing the color of stool. The main difference in diarrhea and normal digestion process is that in diarrhea food passes through intestine so rapidly that intestinal bacteria do not have enough time for converting bilirubin into stercobilin that presents stool it's normal brown color. Gastro-esophageal reflux disease (GERD) is also a disease in which food is rapidly passed through intestines with digestion process.
Cholestasis: In this disease bile flow from the liver into intestine is decreased or stopped. Due to the lack of bile, stools are light-colored. Undigested food particles may come out in stool. In cholestasis, bilirubin, and bile salts may travel into the blood, skin and urine, resulting further complications like Jaundice, Itchy skin and Dark smelly urine. Cholestasis may be due to problems inside or outside the liver.
LIVER DISEASE (intra-hepatic cholestasis): Impaired compressed small bile canals in liver is the cause for outflow of bile from the liver cells. Stool will appear yellow/pale due to appearance of reduced amount of bile in intestine. The possible reasons are Alcoholic hepatitis, Amyloidosis, Cancer that has spread to the liver (liver metastases), Cirrhosis, Lymphoma, Sarcoidosis, Sjögren syndrome, Tuberculosis, Viral hepatitis Vomiting, nausea and tenderness/pain in upper right abdomen are one of the main common symptoms of liver disease.
Gallbladder (Biliary Duct) Disease: Obstruction in biliary duct (through which a bile flows from the liver into intestine) will cause in appearance of less bile in the stool, causing stool yellow, pale, or even grey. Possible causes include Gallstone from the gallbladder, Inflammation (cholangitis), Tumor (cholangiocarcinoma). Cramping pain in upper right abdomen and right below the ribs are common symptoms in gallbladder/biliary duct disease.
Gallbladder (Biliary Duct) Disease: Obstruction in biliary duct (through which a bile flows from the liver into intestine) will cause in appearance of less bile in the stool, causing stool yellow, pale, or even grey. Possible causes include Gallstone from the gallbladder, Inflammation (cholangitis), Tumor (cholangiocarcinoma). Cramping pain in upper right abdomen and right below the ribs are common symptoms in gallbladder/biliary duct disease.
Pancreatic Disease: Biliary duct is pressed by head of enlarged pancreas and thus causing obstruction in bile flow from liver to intestine. Pancreatitis (inflammation of the pancreas) and Pancreatic cyst or cancer may cause this happening.
Abdominal Mass: Bile Duct is pressed by Abdominal tumor (like fibroma) consequently causing cholestasis, and yellow stools. Large tumors can be detected and sensed by hand, or abdominal distension.
