Here's an excellent place to start your research:
http://www.herbmed.org/Herbs/Herb120.htm
As for milk thistle and tx, it is best to discontinue use of milk thistle a couple of weeks before starting treatment and for the duration. There is no evidence of direct interference with interferons or riba, but possibly with the other medications that are prescribed for our side effects. Do a Google on "milk thistle drug interactions" or a variation on the theme. For starters: http://www.thebody.com/catie/milk_thistle.html .
Mike, obviously you've already started your research. The above URL's are hopefully useful additions. (So much for reading too fast while under the influence of a riba headache--sorry!)