BEVERLY HILLS, California (AP) — The liquid is dark red, a mixture of fat and blood, and Dr Mark Berman pumps it out of the patient’s backside. He treats it with a chemical, runs it through a processor — and injects it into the woman’s aching knees and elbows.

The “soup,” he says, is rich in shape-shifting stem cells — magic bullets that, according to some doctors, can be used to treat everything from Parkinson’s disease to asthma to this patient’s chronic osteoarthritis.

“I don’t even know what’s in the soup,” says Berman. “Most of the time, if stem cells are in the soup, then the patient’s got a good chance of getting better.”

It’s quackery, critics say. But it’s also a mushrooming business — and almost wholly unregulated.

The number of stem-cell clinics across the United States has surged from a handful in 2010 to more than 170 today, according to figures compiled by The Associated Press. Many of the clinics are linked in large, for-profit chains. New businesses continue to open; doctors looking to get into the field need only take a weekend seminar offered by a training company.

Berman, a Beverly Hills plastic surgeon, is co-founder of the largest chain, the Cell Surgical Network. Like most doctors in the field, he has no formal background in stem cell research. His company offers stem-cell procedures for more than 30 diseases and conditions, including Lou Gehrig’s disease, multiple sclerosis, lupus and erectile dysfunction.

There are clinics that market “anti-aging” treatments; others specialise in “stem-cell facelifts” and other cosmetic procedures. The cost is high, ranging from US$5,000 to US$20,000.

Berman and others point to anecdotal accounts of seemingly miraculous recoveries. But while stem cells from bone marrow have become an established therapy for a handful of blood cancers — and while there are high hopes that the cells will someday lead to other major medical advances — critics say entrepreneurs are treating patients with little or no evidence that what they do is effective, or even safe. They point to one stem-cell doctor who has had two patients die under his care.

“It’s sort of this 21st century cutting-edge technology,” says Dr Paul Knoepfler, a stem cell researcher at the University of California at Davis. “But the way it’s being implemented at these clinics and how it’s regulated is more like the 19th century. It’s a Wild West.”