Last week about a million cockroaches swarmed Dafeng, a city in Jiangsu province. The source was a nearby plastic greenhouse that was vandalized by an “unknown perpetrator.” Yet the saboteur might be less interesting than what he sabotaged: A medicinal cockroach farm.

It turns out China has a booming trade in cockroaches that can earn as much as 1200 yuan per kilogram, or $89 per pound. The roaring roach trade began when a Yunnan medical professor noticed elderly ethnic minorities in the area’s mountains pulverizing roaches to cure bone tuberculosis. It took more than a decade of research, but he eventually figured out what they were up to, patenting roach powder as a traditional Chinese medicine (TCM) ingredient and cooperating with what’s now perhaps the biggest world’s biggest producer of medicinal raw cockroach-related materials. The powder is used to treat cirrhosis, breast cancer and other ailments, and reputedly also has anti-aging effects (links in Chinese).

But even with a large-scale farm in Yunnan, there’s not enough ground-up cockroach powder (link in Chinese) to meet demand. That’s why Wang and other gutsy entrepreneurs have taken up “cockroach ranching,” as the New York Times’ Chris Buckley put it. And some are already making a tidy bundle.

Take for example Zou Hui (pictured below), who’s kind of a poster woman for roach-breeding. Zou was working as a laborer in Ningbo, on China’s eastern coast, when she had her Paul-on-the-road-to-Damascus moment. After happening to catch a TV program on the discovery in Yunnan, she found herself “moved by the urge to breed roaches,” quit her job and moved back home to Sichuan province to realize her dream.

Sichuan Sannong News Hui and some of her prized investments.

Now five major pharmaceutical companies are customers of her 90,000-strong roach farm, helping her earn a net profit of 60,000 yuan last year—a relatively tidy sum in rural Sichuan. The local town planning commission has christened Zou a “wealth expert” and encouraged her to start the Sichuan Treasure Cockroach Farming Cooperative (links in Chinese).

But not everyone’s excited about the China’s roach rush. Villagers in Shandong province say escapees from nearby breeding farms are infesting their homes. A visit to a farm in the area proved that the screen door system seemed a little unreliable. In addition to teeming masses of cockroaches (link in Chinese), tuyuan (“ground beetles”) are also being raised—they’re good for swelling of the liver and spleen, and pelvic tumors.

Unfortunately for the unhappy neighbors, roach demand is skyrocketing. About 1,000 tons a year are currently available, but the TCM industry needs an estimated 3,000 tons. And the barriers to entry aren’t high: Kits and how-to guides are available online for raising roaches and ground beetles.

A mere 360 yuan teaches the ins and outs of ground beetle-raising technology through seven DVDs, three illustrated guides and a 24-volume e-book.

After that, all an entrepreneur needs is larvae. And not even that many—for each pair of mating cockroaches, around 10 million baby roaches are born (link in Chinese) a year. Talk about a growth industry.