“Negative ion” tampons for women. High-tech shoe pads for improving sleep. Jujube tea for curing cancer.

Over the last 15 years, China’s Quanjian Group grew from obscurity into a $3 billion-a-year alternative medicine empire by peddling products that were as incredible as the company’s meteoric rise. Years of doubts voiced by medical professionals — and even a tough investigation by China’s influential state broadcaster — failed to slow the company’s growth.

The story of Zhou Yang might.

A group of Chinese doctors this week sparked a national sensation after they posted an account of how they dug into Quanjian’s ad campaigns and found a cancer-stricken 4-year-old girl in northern China who was taken off chemotherapy in 2012 on the advice of executives from Quanjian, who gave her jujube powder and gromwell root oil aromatherapy. The executives plastered Zhou Yang’s face on a countrywide ad campaign for their cancer therapy, the doctors said. Zhou Yang’s parents eventually put her back on chemo, but she died in 2015.

The story of little Yang — and other accounts collected by the doctors of Quanjian’s alleged quackery — went viral this week as soon as it hit a Reddit-like Chinese forum called DXY.cn, getting hundreds of thousands of shares and dominating Chinese social chatter.

The online allegations against Quanjian, which spurred blanket media coverage and a government investigation, touched a sore spot in China, where outrage is building among citizens over bogus health-care products and misleading ads that take advantage of poor consumer education, particularly among the elderly and poor.

The story also raised the question of whether a group of citizens can take down a corporate giant in a country where whistleblowers face huge risks and retaliation, as seen in other recent cases.

Quanjian has flatly denied the doctors’ account and said it would sue to protect its reputation. But it has already taken a massive hit. Major Chinese e-commerce platforms — including JD.com, Suning and Vipshop — removed all Quanjian products on Thursday. Regulators in Tianjin, where Quanjian’s headquarters is located, launched an investigation and said they would try to verify the allegations in DXY’s post.

“We have demanded that Quanjian make a comprehensive and honest clarification on this issue,” the government investigators said Thursday.

In their initial blog post on DXY.cn, the doctors said Quanjian first talked in 2012 to the family of Zhou Yang, who had been diagnosed with a rare type of cancer, persuading them to suspend the girl’s chemotherapy and switch to alternative treatment.

The DXY article claimed that Yang’s father — a farmer with little education — made the decision after meeting at Quanjian’s headquarters with its chairman, who allegedly vouched for the efficacy of his company’s homeopathy.

“We talked for about 40 minutes, and he told us Quanjian is China’s largest base for the research and development of traditional Chinese medicine, and that it had a secret anti-cancer drug that could cure my daughter,” the father, who goes by the pseudonym Zhou Erli, told the Shanghai-based news portal ThePaper.com this week.

Quanjian’s anti-cancer remedies, which included sachets of jujube powder for oral intake and gromwell-root oil for aromatherapy, did not stop malignant germ-cell tumor growths in Yang, the father said.

In March 2013, the girl had to be sent back to the hospital for regular treatment. But Yang’s family found that Quanjian had started using the girl’s photos without permission in its online advertising to tout its “miraculous” anti-cancer therapies.

Zhou Erli sued the company in early 2015 over misleading marketing but lost due to insufficient evidence. His daughter died in December that year.

“It was an outright lie, and my daughter had to take those medications for four whole months,” the father said this week.

DXY's “in-depth” report cited a dozen court judgments and previous media reports.

In response, Quanjian released a statement Wednesday saying it never claimed that the company’s therapies cured Zhou Yang. In addition, the company accused DXY of libel and threatened legal action if it did not issue a retraction and apology.

But the doctors on DXY, who signed their real names in posts, did not back down. They said they stand by their allegations and accused Quanjian of also running pyramid schemes and failing to disclose its products’ safety data.

"We are responsible for every single word we have said, and even welcome a lawsuit from Quanjian,” the doctors said in their latest post.

Many Chinese say they believe the doctors who were going after the medical behemoth. In fact, the risks of going up against powerful companies in China are well known. Earlier this year, a Chinese physician was arrested for criticizing a traditional medicinal liquor brand called Hongmao, which claimed that it could cure ailments for the elderly.

The doctor was released after spending almost 100 days in jail, but the case prompted widespread fears that it could set a precedent and silence scientific debate about traditional remedies.

Sean Tan, a 28-year-old office worker in the southern city of Guangzhou, expressed concerns over the ability of big companies to use criminal law to punish critics.

“DXY will find itself facing pressure from all around,” Tan said. “After all, Quanjian has got powerful supporters and could do anything to protect its own interests.”

Quanjian also owns the Chinese Super League soccer team Tianjin Quanjian, as well as more than 600 hospitals and 7,000 health-care clubs across China. Quanjian’s founder, Shu Yuhui, who has described himself as a “gentleman merchant” and purveyor of time-honored recipes, is said to be worth $1.5 billion.

“It is not impossible for Quanjian to seek retaliation against whistleblowers in the same way Hongmao Liquor is doing,” Tan added.

Zhou Erli, the father, said he plans to file another lawsuit against the company in the coming weeks, given the renewed attention to his case.

“Now I have enough evidence to prove that they had tricked us,” Zhou said. “I want to live to see the day when Quanjian gets the punishment it deserves.”