No, not a cure... unfortunately. It should make you more regular though. I assume you were prescribed it because you have IBS-C (or you go back and forth from C to D)? The first couple months on it, it worked like a gem. I was "going" everyday and wasn't having any bad D episodes anymore. It seemed to fix my constant C and my occasional D. After a couple months it seemed as though I built up a tolerance and I would start to skip days again (only poop every other, or every couple days). No worries though, I stayed on it because I knew it was still helping. My doctor told me that new studies have shown that long term use is not harmful; that I can stay on as long as I want (or until she thinks I'm ready to try nothing and manage my IBS on my own).
So, if you get D from Zelnorm that is normal for up to a week. However, if you get dizzy or bloody stool or extreme D, then stop and call a doc ASAP. If you get only a headache like me, pop some headache med and hang in there.
I really hope it works for you. I am much saner now that I'm on Zelnorm (and Digestive Advantage & probiotics - the combo is great for me). Feel better this weekend and tell us how it goes.