Black Tongue

Hello,

About a month or two ago, I had my first experience of waking up with a black tongue and after doing some research, many cases were linked to pepto bismol, which I had in fact taken the night before. It cleared up that very day and all was well.  

Today, I am seeing my tongue slowly turn black again. I did not take pepto bismol or any medicine for that matter. All I know is that I had a lot of yogurt, 2 cups of coffee, and some oreos.  I'm concerned, what could be causing this?

Please help. I've had two bouts of black of tongue within a 3 month period for the first time in my life. The first was explainable but this one is not!

[scottma]

Most discolorations of oral  cavity are extrinsic, which generally result from food or  production of chromagenic bacteria. If the discloration persists more than a week, seeing an oral pathologist is advised.