Pu-erh(yes...POO-air) is a post-fermented(fermented+aged) tea that was made famous in the Yunnan region of southwestern China. Like a fine wine, pu-erh gets better with age. It is used medicinally throughout the world. It can have a very dark, rich, earthy flavor. Because of its richness, I have used it in the past when I wanted to take coffee out of my diet. While it can be a little pricey, the beverage can be steeped multiple times and some say it gets better with each infusion. It is mildly caffeinated, so beware if you avoid or react strongly to caffeine. Pu-erh does lots of wonderful things:
There are many types of pu-erh. Some are cheap(not recommended) and some are really expensive(go crazy!). I recommend researching companies before you buy and only drinking organic fair trade teas. There is also an entire world of pu-erh out there. Once you get into it, you will find there is so much to explore!
Though it is time-tested and some research has been completed, more research needs to be done to fully validate these statements.