In this age of runaway health care costs, prayer, meditation and deep breathing are still free.

Biofeedback, hypnosis and guided imagery have no adverse side effects.

Yoga, massage and vegetarian diets can be combined with over-the-counter and prescription drugs without fear of an overdose or negative drug interaction, and acupuncture and chiropractic care can relieve a lot of pain without chemicals.

That's good news for more than one-third of all U.S. adults who use complementary and alternative medicine - 62 percent when megavitamins and prayer specifically for health reasons are included in the definition, according to a giant new government survey.

CAM is a group of diverse medical and health care systems, practices and products that are not considered part of conventional medicine as practiced by physicians holding M.D. or D.O. degrees or the physical therapists, psychologists, nurses and dietitians who work with them, according to the National Center for Complementary and Alternative Medicine, a component of the National Institutes of Health.

The NIH and the National Center for Health Statistics took the survey to find out how many of us are using CAM, what therapies we are using most and for what health problems and concerns.

Respondents said they use CAM most often for back, neck, head and joint aches, colds, anxiety and depression, sleeping problems and gastrointestinal disorders.

As for their reasons for choosing CAM, most respondents (55 percent) said they believe that it will improve health when used in combination with conventional medical treatments.

The question, which allowed for more than one choice of answers, found that 50 percent believed that CAM would be interesting to try, 28 percent believed that conventional medical treatments would not help them, 26 percent said a conventional medical professional suggested CAM and 13 percent said conventional medical treatments are too expensive.

Most adults who have ever used CAM have used it in the past 12 months, and prayer is by far the most common form of complementary medicine.

The 10 most often used forms of CAM include:

Prayer for one's own health | 43 percent

Prayer by others for one's health | 24.4 percent

Natural products | 18.9 percent

Deep breathing exercises | 11.6 percent

Participation in prayer group for one's own health | 9.6 percent

Meditation | 7.6 percent

Chiropractic care | 7.5 percent

Yoga | 5.1 percent

Massage | 5 percent

Diet-based therapies | 3.5 percent

The most commonly used natural products were echinacea (40.3 percent), ginseng (24.1 percent), ginko biloba (21.1 percent) and garlic supplements (19.9 percent).

From nccam.nih.gov.