Don't buy ordinary pau d'arco capsules, as you can't efficiently digest the active principles in the bark. If you want an extract that is STRONG and comes in capsules try Vibrant Life's Taheebo Life Tea. It is wonderful, I'm not kidding. I have found some of the teas are quite bitter, but Wisdom of the Ancients (also called Wisdom Naturals) pau d'arco tea never is. It seems to help with absorption of wonderful stuff in pau d'arco if you put some lemon juice or apple cider vinegar in after you have simmered it for at least 1/2 hour and then let it cool.