Yarchagumba is caterpillar fungus, or by its more prominent names yartsa gunbu. It is an entomopathogenic fungus (a fungus that grows on insects) in the family Ophiocordycipitaceae. It is mainly found in the meadows above 3,500 meters (11,483 feet) on Tibetan Plateau in Southwest China and Himalayan regions of Bhutan and Nepal. It parasitizes larvae of ghost moths and produces a fruiting body which used to be valued as a herbal remedy and in traditional Chinese medicine. Caterpillar fungus contains the compound Cordycepin, an adenosine derivative. However, the fruiting bodies harvested in nature usually contain high amounts of arsenic and other heavy metals so they are potentially toxic and sales have been strictly regulated.