Brief Answer: likely related to medication Detailed Answer: HI, thanks for using healthcare magic Famotidine can be associated with changes in stool colour. Most commonly it can be associated with black tarry stools but in some persons, the stool can have a whiter appearance. The exact reason is not known. As you mentioned , blockage of the flow of bile can also cause a pale appearance to the stool. This occurs in disease of the liver, gallbladder or pancreas. In the absence of any other symptoms that can be related to these organs (abdominal pain, jaundice, fever), then this is less likely the cause. You should consider monitoring the stool colour, if it continues, your doctor may consider liver function blood tests as a precaution, though it is likely medication related. I hope this helps, feel free to ask any additional questions

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