Hiya Nam! :)
RenewLife products are suspect because the creator of the line was a former employee of another line of health products who left and went into competition with them, but chose weaker herbal complexes to increase profits at least with the anti- parasite
product. Her book is highly regarded, however.
Herbal complexes for the liver can be very effective! when I first started cleansing I cleansed my liver with just herbs and diet and fresh veggie juices, I didn't start flushing right away, and still had great results. Good herbal products for the liver are listed in the Liver Notes, be sure to read that and check them out, they're easily found with national distribution. :)