I would not rely on Pau d'arco because too many of the suppliers dont give the medicinal part of the inner bark in their mix. I think Essiac tea is better suited as you have more chance of having the right herbs I mean Sheeps Sorrel is sheeps sorrel. The only thing you might have to worry about is how its processed etc but this goes for Pau D'Arco. As in my thread below I believe in Pau D'Arco from the proper inner bark and if you can grab hold of it then WOWZA. As for Gravolia I suggest PawPaw more so as its far more stronger and the only stuff that can easily kill MDR cells (multi Drug Resistant). Add a little pineapple every other day for natural Bromelain and WOWZA.