Alternative Medicine Goes Mainstream

But sometimes the cost is far greater. Cancer patients can lose their only chance of beating the disease by gambling on unproven treatments. 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 have been 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.

The latest government survey shows the magnitude of risk: 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. Some states license certain types, like acupuncturists; others do not.

Tens of millions of Americans take dietary supplements -- vitamins, minerals and herbs, ranging from ginseng and selenium to fish oil and zinc, said Steven Mister, president of the Council for Responsible Nutrition, an industry trade group.

"We bristle when people talk about us as if we're just fringe," he said. Supplements are "an insurance policy" if someone doesn't always eat right, he said.

In fact, some are widely recommended by doctors -- prenatal vitamins for pregnant women, calcium for older women at risk of osteoporosis, and fish oil for some heart patients, for example. These uses are generally thought to be safe, although independent testing has found quality problems and occasional safety concerns with specific products, such as too much or too little of a vitamin.

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 Dr. Jeffrey White, complementary and alternative medicine chief at the National Cancer Institute. A doctor with a big interest in nutrition, he sees the field as "an area of opportunity" that deserves serious study.

So does Dr. Josephine Briggs, director of the National Center for Complementary and Alternative Medicine, the federal agency Congress created a decade ago.

"Most patients are not treated very satisfactorily," Briggs said. "If we had highly effective, satisfactory conventional treatment we probably wouldn't have as much need for these other strategies and as much public interest in them."

Even critics of alternative medicine providers understand their appeal.

"They give you a lot of time. They treat you like someone special," said R. Barker Bausell, a University of Maryland biostatistician who wrote "Snake Oil Science," a book about flawed research in the field.