Most people suffer from a case of the creepy-crawlies when they hear what workers at a drug company in Xichang, Sichuan province, do to earn their keep.

Specialists at Sichuan Good Doctor Panxi Pharmaceutical Co are charged with "taking care" of some 6 billion cockroaches.

The cockroaches are harvested to make drug precursors that treat ailments including gastric bleeding, gastric and oral ulcers, as well as most burns.

According to Wen Jianguo, general manager of the company, 3.6 billion adult cockroaches are cleaned and harvested annually to extract useful components.

Visitors to the facility must don white gowns and gloves, and their cellphones are thoroughly disinfected to prevent unwanted microorganisms from entering.

Unlike cockroaches in the wild, the specimens at Panxi live in a germ-free environment so that medicines are pathogen free, Wen said.

Computers precisely control temperature and humidity, and the insects eat at fixed times.

The roaches are fed powdered wheat, corn and vegetables with trace elements. Each day, they consume about 10 metric tons and create 3 tons of droppings, Wen said.

There are more than 100 cockroach facilities similar to Panxi in Xichang as well as Dali, Yunnan province.

The popularity of roach bases has much to do with the pioneering work done by Li Shunan, former president of the Institute of Drug Research at Dali University.

The 82-year-old professor started his systematic research into cockroaches in 1963, trying to extract effective chemical components from them.

As it was difficult to extract the components, Li began working with Hu Zhong, a research fellow with the Chinese Academy of Sciences' Kunming Institute of Botany in 1983.

They used to collect thousands of cockroaches, dissolve them into bits with chemical agents, and look for useful chemical compounds, Li said.

After many experiments, they managed to find key components that helped heal wounds, and synthesized a marketable drug.

As the medicine proved to have no side effects, the pharmaceutical plant affiliated with the Chengdu Military Area Command started producing it in 1985.

The success of Li and Hu stimulated more research into drugmaking with roach components and the establishment of bases to breed and harvest the insects.