BALTIMORE - At one of the nation's top trauma hospitals, a nurse circles a patient's bed, humming and waving her arms as if shooing evil spirits. Another woman rubs a quartz bowl with a wand, making tunes that blend with the beeping monitors and hissing respirator keeping the man alive.

They are doing Reiki therapy, which claims to heal through invisible energy fields. The anesthesia chief, Richard Dutton, calls it "mystical mumbo jumbo." Still, he's a fan.

"It's self-hypnosis" that can help patients relax, he said. "If you tell yourself you have less pain, you actually do have less pain."

Alternative medicine has become mainstream. It is finding wider acceptance by doctors, insurers and hospitals like the shock trauma center at the University of Maryland Medical Center.

People turn to unconventional therapies and herbal remedies for everything from hot flashes and trouble sleeping to cancer and heart disease. They crave more "care" in their health care. They distrust drug companies and the government. They want natural, safer remedies.

But often, that is not what they get. Government actions and powerful interest groups have left consumers vulnerable to flawed products and misleading marketing.

Dietary supplements do not have to be proved safe or effective before they can be sold. Some contain natural things you might not want, such as lead and arsenic. Some interfere with other things you may be taking, such as birth control pills.

"Herbals are medicines," with good and bad effects, said Bruce Silverglade of the consumer group Center for Science in the Public Interest.

Contrary to their little-guy image, many of these products are made by big businesses. Ingredients and their countries of origin are a mystery to consumers. They are marketed in ways that manipulate emotions, just like ads for hot cars and cool clothes.

Even therapies that may help certain conditions, such as acupuncture, are being touted for uses beyond their evidence.

An Associated Press review of dozens of studies and interviews with more than 100 sources found an underground medical system operating in plain sight, with a different standard from the rest of medical care, and millions of people using it on blind faith.

How did things get this way?

Fifteen years ago, Congress decided to allow dietary and herbal supplements to be sold without federal Food and Drug Administration approval. The number of products soared, from about 4,000 then to well over 40,000 now.

Ten years ago, Congress created a new federal agency to study supplements and unconventional therapies. But more than $2.5 billion of tax-financed research has not found any cures or major treatment advances, aside from certain uses for acupuncture and ginger for chemotherapy-related nausea. If anything, evidence has mounted that many of these pills and therapies lack value.

Yet they are finding ever-wider use:

Big hospitals and clinics increasingly offer alternative therapies. Some offer treatments with little or no scientific basis, to patients who are emotionally vulnerable and gravely ill.

Health insurers are cutting deals to let alternative-medicine providers market supplements and services directly to members. Some insurers steer patients to Internet sellers of supplements even though patients must pay for these out of pocket.

A few herbal supplements can directly threaten health. A surprising number do not supply what their labels claim, contain potentially harmful substances like lead, or are laced with hidden versions of prescription drugs.

"In testing, one out of four supplements has a problem," said Tod Cooperman, president of ConsumerLab.com, an independent company that rates such products.

Even when the ingredients aren't risky, spending money for a product with no proven benefit is no small harm.

But sometimes the cost is far greater. Cancer patients can lose their only chance of beating the disease. People with clogged arteries can suffer a heart attack. Children can be harmed by unproven therapies forced on them by parents who distrust conventional medicine.

Mainstream medicine and prescription drugs have problems, too. Popular drugs such as the painkillers Vioxx and Bextra were pulled from the market after serious side effects emerged once they were widely used by consumers. But at least there are regulatory systems, guideline-setting groups and watchdog agencies helping to keep traditional medicine in line.

The safety net for alternative medicine is far flimsier.

More than a third of Americans use unconventional therapies, including acupuncture, homeopathy, chiropractic, and native or traditional healing methods. These practitioners are largely self-policing, with their own schools and accreditation groups.

Tens of millions of Americans take dietary supplements - vitamins, minerals and herbs, ranging from ginseng and selenium to fish oil and zinc.

Some are widely recommended by doctors - prenatal vitamins for pregnant women and calcium for older women at risk of osteoporosis, for example. These uses are generally thought to be safe, although testing has found quality problems with specific products.

Some studies suggest that vitamin deficiencies can raise the risk of disease. But it is not clear that taking supplements will fix that, and research has found hints of harm, said Jeffrey White, complementary and alternative medicine chief at the National Cancer Institute.

The industry has stepped up self-policing - the Council for Responsible Nutrition hired a lawyer to work with the Council of Better Business Bureaus and file complaints against outlandish marketing claims.

The FDA just issued its first guidelines for good manufacturing practices, aimed at improving supplement safety. Consumer groups say the rules don't go far enough, but give the FDA more leverage.