I was on Flagyl for 2 months with no problems. A week after starting 6mp along with the Flagyl, the tops of my feet and behind my left ankle went numb. My doctor blamed it on the Flagyl and took me off of it. I am still on 6mp. I have been off Flagyl for 3 months, and my feet are not as numb, but still not perfect. On the other hand, my Crohn's seems to be under control, so I'll keep the numbness in exchange for no Crohn's symptoms.