Ingredients of Shady Origins, Posing as Supplements

More traditional Chinese medicine.

DR. PIETER COHEN is scanning the shelves inside a shop in Chinatown here when something familiar — and potentially dangerous — catches his eye.

“What’s that yellow box, behind the other one?” Dr. Cohen asks the clerk.

It is Pai You Guo, a supposedly natural weight-loss supplement from China that, according to federal authorities, has tested positive in the past for containing two hazardous drugs, including a suspected carcinogen. The product was recalled in 2009. One of Dr. Cohen’s patients in the Boston area ended up in the hospital last year with a range of ailments after taking Pai You Guo, a brand-name that, loosely translated from Chinese, means “the fruit that eliminates fat.”

But he has seen worse: kidney failure, heart problems, depression, addiction — all, he says, caused by tainted products sold openly as dietary supplements in shops across the nation and on the Internet.

“My patients are being harmed by this,” says Dr. Cohen, an internist at the nearby Cambridge Health Alliance and an assistant professor of medicine at Harvard Medical School.

Marketing drugs in the guise of supplements is illegal in the United States. Tainted Pai You Guo is just one small part of that global business. Federal authorities are struggling to identify and intercept these black-market goods, which, they warn, pose grave health risks.

The makers of legal dietary supplements — the kind found at GNC, for example — acknowledge they are reluctant to raise too many alarms. Even though there is little evidence that many dietary supplements provide real health benefits, legal supplements, from multivitamins to ginkgo biloba, are a big and growing business. Americans spent $28.1 billion on them last year, up from $21.3 billion five years ago, according to estimates from Nutrition Business Journal, a market research firm.

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