Caterpillar fungus are known as yartsa gunbu (དབྱར་རྩྭ་དགུན་འབུ།) in Tibet—yartsa means summer grass, gunbu means winter worm. In Chinese it’s called “chongcao” or “dong chong xia cao” which also translates to “summer grass winter worm.” It’s a rare herb found in Tibet and other Himalayan regions and only grows above an altitude of 4000 meters. The fungus is highly valued for its purported medicinal benefits, for instance, as a treatment for cancer and aging, high blood pressure, as a libido booster and as an immune system booster. This is why the fungus is so popular among Han Chinese people in mainland China, and even in some western countries. Demand for the fungus has soared.
May and June are the harvest season for caterpillar fungus. Tibetan Nomadic yak herders and farmers leave their home and set up tents near the mountains for the harvest. They collect the caterpillar larvae with its parasitic fungus whole from the ground. This highly prized medicinal fungus has mostly been traded to China for centuries. During the short harvest period a prolific harvester can earn more than enough cash to live on for an entire year. In the last few decades harvesting caterpillar fungus has developed into the main source of income for rural Tibetans.
Every spring business traders from China travel to Tibet to collect caterpillar fungus from local people. The Chinese grind up the fungus and sell it as a powder, use it whole as a garnish, cook it with soup and drink it with tea. It costs 30-70 RMB for a single caterpillar fungus, though it also depends on where and who you buy from. It’s cheaper if you buy from local Tibetans and more expensive if you buy from shops in mainland China, due to the processing and packaging. It’s better to get local people’s help if you want to purchase some because there are fakes in the market.