I think the herbal you read about
was psyllium powder. It had the same effect on me that the fiber supplements did, but there are others that have had success with it.
I would talk to your GI about the cholestyramine if fiber is failing you. I get the generic and sugar free (artificially sweetened) version. A long time ago I used the brand name Questran and it was amazing back then too - they just stopped making the sugar free version. The sugar sweetend one made me nauseous every time I took it. It has a little bit of orange flavoring in it. I add 1 packet a day (low amount per others on here and my doc loves I need only 1) to pulp free OJ couple of ounces and rinse the "crumbs down with a little more water.
Hope it can help you like it has me!