A majority of Americans are now trying to cure their ills with prayer or unconventional remedies, including herbal tonics, acupuncture, massage and yoga, federal researchers reported yesterday.

A new government survey of more than 31,000 U.S. adults nationwide, the most comprehensive assessment of the use of alternative medicine in the United States, found that 36 percent are using some kind of "complementary and alternative" therapy. That number jumps to 62 percent when prayer is included.

About one-fifth of Americans use "natural" supplements such as herbs and enzymes, with echinacea being the most popular, used by 40 percent of those surveyed, followed by ginseng (24 percent), ginkgo biloba (21 percent) and garlic (19 percent). Twelve percent use deep-breathing exercises for medical reasons, 8 percent meditate, 5 percent do yoga, 5 percent get massages and 4 percent try diets, the survey found.

The findings underscore the need to evaluate the safety and effectiveness of such therapies, especially given the findings that some Americans are continuing to try products such as kava kava, which is used to treat anxiety but has been linked to possible liver problems, officials said.

"The public makes the assumption that because something is natural that it is safe," said Richard L. Nahin, a senior adviser at the National Institutes of Health's National Center for Complementary and Alternative Medicine, which commissioned the study. "These products can be unsafe."

Still, many say they have found relief from pain and disease by using unconventional remedies. Phyllis McDonald, 84, of Falls Church said she suffered for years from agonizing back pain until a combination of acupuncture, spinal manipulation and physical therapy gave her relief.

"It was horrible," McDonald said. "Now I'm ballroom dancing."

Women, highly educated people, those who had been hospitalized in the past year and former smokers were the most likely users, the survey found.

Back, neck, head and joint aches; colds; insomnia; stomach problems; anxiety; and depression are the leading ills people try to cure, according to the survey.

Richard Miller, 55, a retired dentist from Arlington, said he battled debilitating headaches until acupuncture and spinal manipulation began to help. "I wouldn't say I'm cured, but it's so much better," he said.

But such remedies are also used for high blood pressure, high cholesterol, and symptoms of menopause, asthma, diabetes and even sometimes cancer, the researchers said.

A majority of people -- 55 percent -- combine alternative treatments with conventional medicine, but 13 percent try them because they think conventional medicine is too expensive, and 28 percent -- more than in earlier surveys -- believe conventional medical treatments will not help their health problems.

"This is the medicine of the future," said Gary Kaplan, who treated McDonald at his Arlington clinic, one of a growing number of centers that combine traditional medicine with alternative therapies. "I think it's taking the best from every tradition."

Prayer is the most popular way sick people seek help outside a doctor's office, with 43 percent saying they pray for their own health and 24 percent praying for others, the survey found.

The survey, conducted by the federal Centers for Disease Control and Prevention's National Center for Health Statistics, confirms earlier, much smaller studies, which found that the popularity of alternative therapies was rapidly rising. The new findings provide much more detail than ever before and indicate that trend was continuing unabated

"These new findings confirm the extent to which Americans have turned to [alternative] approaches with the hope that they would help treat and prevent disease and enhance quality of life," said Stephen E. Straus, director of the National Center for Complementary and Alternative Medicine.

The findings make it clear that alternative medicine has established itself as an integral part of the U.S. health care system, said David M. Eisenberg of Harvard Medical School in Boston, who conducted similar smaller surveys in the past.

"This should lay to rest any question as to whether this is a momentary fad," he said. "I think what it argues fairly convincingly for is the need for more research to figure out which of these therapies work and which don't, which are safe and which are not, how these work when they work, and whether access to these therapies will increase costs or decrease costs."

The survey, conducted in 2002, included questions on 27 types of alternative therapies commonly used in the United States, including 10 types provided by such practitioners as acupuncturists and chiropractors and 17 others that people do on their own, such as herbal and botanical remedies, special diets, and megavitamins. Previous surveys included far fewer therapies and many fewer people who were not interviewed in depth and in person.

While the American Herbal Products Association praised the results, the findings raised concern among some mainstream medical authorities.

"There is no scientific evidence to confirm the safety or efficacy of alternative therapies," William G. Plested III of the American Medical Association said in a statement. "Patients turning to alternative therapies should advise their physicians so that any risks that can result from postponing or stopping conventional medical treatment can be fully discussed."

Wallace Sampson, a professor emeritus at the Stanford University School of Medicine who edits the Scientific Review of Alternative Medicine, criticized the survey and the federal government's funding research to evaluate such therapies as a waste of taxpayer money.

"How much did it cost the American public to find out what we already knew?" he asked. "It's a tax-supported market survey for supplement makers."

Similarly, Saul Green, a retired biochemist at the Memorial Sloan-Kettering Cancer Center in New York, said there remained no evidence that any of these treatments work and growing evidence that they can cause harm.

"There is no scientific evidence for the efficacy of any one of these treatments," Green said in an e-mail. "They have been sold a bill of goods."

The Food and Drug Administration, for example, recently ordered the popular herbal weight-loss product ephedra off the market.

While Nahin agreed that some products can cause problems, such as interfering with conventional medications, in many cases they may be helpful. "If people are using complementary and alternative medicine in lieu of a conventional medicine that works, that's cause for concern. If they are using it as an adjunct to conventional care and it doesn't interfere with conventional care and has no harmful side effects on its own, it probably isn't a cause for concern," he said.

Maggie Covington, a family physician who integrates various forms of medicine at Wisneski Health Associates in Bethesda, agreed.

"The distinctions between alternative and conventional are really going to have to fall away," she said. "We have to look for a type of medicine that addresses not just the physical aspect of the disease but the whole picture -- the physical, the spiritual and the emotional."