For the Nanjing Brain Hospital, Mr. Xing said, he was told to promote its treatment success rate as 100 percent. He also made up testimonials, including one of a woman in Nanjing who was cured of anxiety after going to a Putian-related hospital.

“Everything was fabricated by us,” he said. “None of them was a real case.”

Mr. Xing said he and his colleagues had been given templates. “We had to exaggerate the harm caused by the disease,” he said. “The more exaggerated, the better.” The company, he said, had a “professional art team” that would steal online photographs of other people and stick them onto testimonials.

Mr. Xing resigned after two weeks.

“This phenomenon doesn’t only pertain to the Putian network, right?” Mr. Wu of the Putian health association said. “All over the internet, it’s likely that there are many other businesses who engage in that.”

Putian tapped the power of the internet to expand, plowing profits into marketing. Liang Jianyong, a former Communist Party secretary in Putian, said the network invested $1.8 billion in advertising on the Chinese search giant Baidu in 2013. It amounted to nearly half the search engine’s advertising revenue that year, according to the National Business Daily. Baidu declined to comment.

Many of the online marketing materials have a similar feel. They feature dozens of specialists, with lengthy résumés promoting “abundant clinical experience” and “praise from peers within the industry.” There are glowing testimonials from satisfied patients with emotional narratives.

One details the case of a father who “knelt down” pleading with the chief doctor at the Putian-linked Edward Hospital, in the far western region of Xinjiang, to treat his 5-year-old daughter. She received treatment that was “the most advanced technology in the world.”

Some Putian hospitals promoted credentials they didn’t have. Two of the nine doctors advertised on Shenyang Metropolis Hospital’s website are not accredited to work there, according to an analysis of a doctor database run by the National Health and Family Planning Commission, the government agency.