During spring 1996, random samples of adult primary care physicians, obstetrics-gynecology physicians and nurse practitioners, and adult members of a large northern California group practice model health maintenance organization (HMO) were surveyed by mail to assess the use of alternative therapies and the extent of interest in having them incorporated into HMO-delivered care. Sixty-one percent (n = 624) of adult primary care physicians, 70% (n = 157) of obstetrics-gynecology clinicians, and 50% (2 surveys, n = 1,507 and n = 17,735) of adult HMO members responded. During the previous 12 months, 25% of adults reported using and nearly 90% of adult primary care physicians and obstetrics-gynecology clinicians reported recommending at least 1 alternative therapy, primarily for pain management. Chiropractic, acupuncture, massage, and behavioral medicine techniques such as meditation and relaxation training were most often cited. Obstetrics-gynecology clinicians used herbal and homeopathic medicines more often than adult primary care physicians, primarily for menopause and premenstrual syndrome. Two thirds of adult primary care physicians and three fourths of obstetrics-gynecology clinicians were at least moderately interested in using alternative therapies with patients, and nearly 70% of young and middle-aged adult and half of senior adult members were interested in having alternative therapies incorporated into their health care. Adult primary care physicians and members were more interested in having the HMO cover manipulative and behavioral medicine therapies than homeopathic or herbal medicines.