I've been taking colonclenz for 2 days maybe 3. I take 2 pills a day. This morning I had diarrhea which was very dark, maybe even black. Is this ok?

See MD. The GI tract moves food, , and eventual stool through the GI tract, so colon cleansing is not ordinarily needed nor should it be taken for any reason. Gi problems that prevent normal bowel movements need to be reported to md colon cleanse may contain laxatives that of course may cause diarrhea. Black stools may represent bleeding in the upper part of the GI tract, so report it to md.