Ophiocordyceps sinensis, known colloquially as caterpillar fungus, is an entomopathogenic fungus in the family Ophiocordycipitaceae. It is mainly found in the meadows above 3,500 metres (11,500 ft) on the Tibetan Plateau in Tibet and the Himalayan regions of Bhutan, India, and Nepal. It parasitizes larvae of ghost moths and produces a fruiting body which is valued in traditional Chinese medicine as an aphrodisiac. 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 by China's State Administration for Market Regulation since 2016.

Bhutan, officially the Kingdom of Bhutan, is a landlocked country in South Asia situated in the Eastern Himalayas between China in the north and India in the south. With a population of over 727,145 and a territory of 38,394 square kilometres (14,824 sq mi), Bhutan ranks 133rd in land area and 160th in population. Bhutan is a constitutional monarchy with a king as the head of state and a prime minister as the head of government. Vajrayana Buddhism is the state religion and the Je Khenpo is the head of the state religion.