If I am not mistaken, Metformin can cause diarrhea. Do an internet search on this. Did this begin after you started taking the Metformin? I am currently taking Avandia. My doctor wanted to put me on MEtformin but becauce I have a history of bowel disorders and diarrhea, I refused and am sticking with the Avandia to control my blood sugar. I am not sure if you even have that option.

If I were you, I would talk to your doctor about what is happening to you and its possible conection to Metformin. He may be able to give you some pretty good advice or even change your meds if this side effect is due to Metformin and does not subside.

Good luck!