Oh my God! Thanks to this blog, because I woke up this morning with the "black tongue" thing and I was sooooo scared that I jumped on the internet to find out why this had occured and just as it so about the Pepto-bismol, I remembered I took two chewable tablets last night.I checked the warning labels and there it was "may cause darkening of the tonuge. I feel so relieved that I found out why this had happen.