Cordyceps sinensis (dong chong xia cao) is an unusual and powerful Chinese mushroom. In nature, it grows at high elevations, where oxygen levels and temperature are low. Cordyceps sinensis (dong chong xia cao) is believed to have been discovered 1,500 years ago in Tibetan mountain pastures when herdsmen observed that their animals became energetic after eating the grass-shaped fungi. Since then, it has found a place in traditional Chinese medicine as an energy tonic. Modern research is just beginning to discover cordyceps‘ many health benefits. In clinical studies, cordyceps was shown to be an effective complementary treatment for renal and respiratory disorders, cerebrovascular disease, elderly fatigue, heart arrhythmia, chronic heart failure, hepatitis B, leukemia, low sperm count, lung cancer, leukemia, atherosclerosis and cardiovascular disease.