I had Xeloda for six weeks. Got diarrhea once I think. I had far worse problems with constipation and would have taken diarrhea over constipation. I also had radiation at the same time. I'm likely on adjuvant Xeloda in a few weeks but I have a temp bag so we'll see what happens. I've avoided Imodium as well (have a couple of packages at home and the warnings were a bit scary). I'm just taking fiber supplements and they're good enough for now. Surgeon said to not be afraid to take Imodium.
Keep up with fluids and electrolytes during diarrhea.