A simple scatological, or is it pharmacological, question. Why does Pepto-bismol turn turds dark colored?
nm ‘’…sulfur in saliva and the colon to form bismuth sulfide.’’
SDMB is good. I find most of my answer while attempting to write the question.
Since you answered your own question, I’ll chime in with a fun fact- bismuth used to be considered the heaviest non-radioactive element, until it was discovered to be very slightly radioactive.