Extracts of the plant are potential game changers in the fields of medicine, food supplements and cosmetics. Yang Wanli and Li Yingqing report from Kunming.

A narrow, meandering stony path connects the suburbs of Eshan, a small town in the southwestern province of Yunnan, with a factory perched in the neighboring mountains.

The factory buildings have no windows, so small fans on the roof run constantly to allow fresh air to enter. Inside, workers in lab coats oversee hundreds of pieces of equipment.

"For the first few months after my company started operating, the local police visited the factory several times a week. They suspected we were secretly making illegal drugs in the mountains, like you see in the movies," said Pan Zongbing, CEO of Hankang (Yunnan) Biotechnology.

Rather than illegal activity, the company is focused on extracting substances from hemp plants. Pan opened a small box on his desk and took out several glass vials; some held a white power, while others contained a clear liquid. None emitted any special odor.

"It's cannabidiol, more commonly known as CBD, a nonintoxicating extract (of the Cannabis sativa plant). It has been described as a 'rising superpower', because it is highly valued in the international market and is thought to have great potential in a wide range of uses, including cosmetics, food and, most importantly, medicines," he said.

In the 1950s, the government banned the cultivation and use of marijuana, but in 2010, Yunnan introduced the country's first regulation on the commercial planting and processing of hemp, the industrial strain of the plant.

Since then, hemp has been grown in the province, but the concentration of tetrahydrocannabinol－or THC, the mind-altering ingredient in marijuana－is no more than 0.3 percent, an extremely low level.

Yang Ming, a hemp expert at the Yunnan Academy of Agricultural Sciences, said farmers mainly grow the plant for its seeds, fibers and CBD.

"So far, scientists have identified more than 500 extracts in cannabis plants. Nearly 100 of the extracts are found in the flowers and leaves. The various cannabis plants have different amounts of these extractives, and the one called 'industrial hemp' is a legal crop in many countries," he said.

He added that CBD has come under the international spotlight in the past five years after research suggested it could be used to treat many problems, including anxiety and insomnia, and as an analgesic.