I like Yerba Mate also. The one thing I notice is that really triggers peristalsis. When I used to do Colon Cleanses with psyllium, the yerba mate would help have regular bm's.
In fact when I have my morning cup, I can pretty much expect to have a BM immediately afterwards. Not that that's all Yerba Mate's good for. I helps my energy levels, concentration etc. Way better than coffee.
One thing that's really good for the colon besides the cleanses is the Budwig Protocol. I have colorectal tumors and Budwig has really helped. Every morning when take the flakseed oil cottage cheese mix, any colon pain just vanishes and feels wonderful.
At one point I was almost completely stopped up and would have had to have colon surgery. I tried Budwig just to see if it would help as a last stab before scheduling surgery and it worked. It's been years and I'm still doing fine - and still doing Budwig.