How soon after taking pepto bismol will your poop go back to normal color?

The reason for black stool with pepto bismol is that the bismuth in the pepto bismol mixes with the sulphur in the saliva and digestive tract to make bismuth sulfide which is black .The stool can stay black for a few days after stopping the medicine but will clear up and is not a cause for alarm . However if it stays black for a long time after stopping it , it should be checked out.