Pu'erh is the most oxidized of teas. Some Pu'erhs are decades, if not centuries old. Pu'erh is the only tea that has the chemical lovastatin in it. Lovastatin is a prescribed medicine used to help lower cholesterol. Properly aged Pu'erh is known to have "cháqì" a sensation of warmth and bliss that can cause what the Chinese call aptly "Tea Drunkeness".