What Causes Light-Colored Stool
Light-colored stools (grey or clay-colored) in adults can be caused by lack of bile in the digestive system. It is usually from a blockage in the bile ducts, either from a stone or a tumor.
Bile helps digest fats and is responsible for the brown color of stool. It is produced in your liver, stored in your gallbladder, and released into your intestines. If bile is prevented from getting into your intestines, this can cause persistent pale or clay/grey-colored stool.
Conditions causing light-colored stool
1. Obstructed bile duct from tumor
There are a few recorded cases of people having silver-appearing stool—these people all had tumors blocking the bile duct that also bled into the intestine. The combination of digested blood (black tar color) and lack of bile (pale grey color) gives a distinct silver color to the stool. —Dr. Adam Pont
- Painless jaundice (yellowing of skin and whites of eyes)
- Pale or clay/grey colored stools
- Sudden fever and abdominal pain (from infection of the obstructed bile)
Once bile is produced in the liver, it travels by a tube (duct) to your gallbladder, where it is stored until ready to be released into your intestines. Blockages by a tumor along the duct or the surrounding area (including the gallbladder or pancreas) will keep bile from flowing to the intestine, which can cause stool to become pale or grey (and also cause jaundice).
The pale/grey stools or progressively worsening jaundice may be the first sign that something is wrong. You may also get an infection in the blocked bile, called cholangitis. That can cause fever and abdominal pain, and in severe cases, confusion and low blood pressure. Cholangitis is a medical emergency and requires prompt treatment.
If you notice pale/grey colored stools and yellowing of your skin, you should call your doctor for an urgent (within the next couple days) appointment. They will likely do blood tests and get you an urgent appointment with a biliary disease specialist (interventional gastroenterologist).
The specialist will order an imaging test (ultrasound, CT, or MRI) and perform a procedure to view the inside of your intestines and bile ducts, called ERCP, which is done under sedation. Treatment depends on what is found in the tests.
2. Obstructed bile duct from gallstones
- Abdominal pain
- Jaundice (yellowing of skin and whites of eyes)
- Pale or clay/grey colored stools
- Often will have no symptoms
Gallstones are very small stones that can form from the components of bile, a digestive liquid. They are often found in the gallbladder. Gallstones can sometimes block bile from exiting the gallbladder or become stuck in a bile duct, causing an obstruction (choledocholithiasis).
If the stone passes quickly through the duct into your intestine, you may have no symptoms at all. But if the stone becomes stuck, you may experience abdominal pain, jaundice, and pale/grey colored stools. A blockage may also cause an infection (cholangitis). If the stone is stuck in the lower part of the bile duct, it may block digestive fluid from exiting the pancreas, which can cause pancreatitis.
If you notice pale/grey colored stools along with abdominal pain or jaundice, you should go to the ER. You may need a gastroenterologist to perform an imaging test and procedure to clear the stones.
Other possible causes of pale/grey stool
Much less common causes of pale/grey stool or causes where pale/grey stool is not a main symptom include certain medications and acute hepatitis.
When to call the doctor
Call your primary care physician for an urgent appointment (within a couple days) if you have pale/grey stool and jaundice.
One recent technological innovation is the use of a very small flexible camera to directly visualize the inside of the duct itself—called cholangioscopy. This allows the gastroenterologist to see the ducts and any stones or tumors on a live video feed, potentially allowing for more tailored and precise treatments during the procedure. —Dr. Pont
Should I go to the ER for pale or grey stool?
- Abdominal pain
- Dizziness/lightheadedness, especially when sitting up or standing up
- Confusion or lethargy
Treating light-colored stool
In many cases where an ERCP is done, a small plastic or metal stent will be left in your bile ducts to keep them open and allow bile to drain into your intestines. Make sure to ask if or when the stent needs to come out, which will involve a second endoscopic procedure at a later date. —Dr. Pont
Treatment of light-colored stool will be dependent on the specific cause of symptoms. Since there are multiple causes for pale stool, it is important to make an appointment with your doctor to discuss treatment options. These may include:
- ERCP: A procedure that is performed by an interventional gastroenterologist where a flexible scope is passed through your mouth, esophagus, and stomach to your small intestine and then used to view your bile ducts. The doctor can also try to clear out obstructing gallstones during this procedure.
- Surgery: If your clay-colored stools are caused by obstructing gallstones, after an ERCP, your doctor might recommend surgery to remove the gallbladder entirely (cholecystectomy) to help prevent recurrences. In some cases, surgery is required to remove gallstones if ERCP is unsuccessful or unavailable.
- Cancer treatment: If your symptoms are because of cancer, your physician will discuss treatment options that may include surgery, radiation, or chemotherapy.
Dr. Pont is currently a fellow in Gastroenterology at New York Presbyterian Hospital/Columbia, where he also completed his residency in Internal Medicine. Dr. Pont received his medical degree and PhD at the New York University School of Medicine. He earned his BS in Biological Systems Engineering at the University of Nebraska-Lincoln.