Intestinal Formula #1 Causes Colon to Become Black

I've been taking Intestinal Formula #1 for several years. I recently had a colonoscopy. The surgeon told me afterwards that the inside of my colon was completely black making it hard for him to look for polyps. He was concerned with this blackness.
I sent Dr Schulze several emails describing this and asking if I should be concerned but I never received a response which is worrisome in itself.
Does anyone else have this experience or an opinion whether I should be concerned?
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