Yes I have heard that from Dr Schulze people many time until today. Today I called and then totally denied it.
I had been using #1 regularly for many years. Last year, I had a colonoscopy and my surgeon complained it was discolored and told me to get off IF #1. I continued until early May. Back then the DS reps told me if I got off the IF #1, the discoloration would go away in a month. I had another colonoscopy last week and he complained again - it didn't go away. That is why I called back today to check and the rep denied everything and refused to talk.
When I left IF #1 I started on Herbamucel. I wonder if something in it is causing the problem. The only other possibilities are that something in the Herbamucel did it or the long term use of IF #1 discolored it permanently or will go away much slower than they said.