Background - The interest in complementary and alternative medicine (CAM) has increased during the past decade and the attitude of the general public is mainly positive, but the debate about the clinical effectiveness of these therapies remains controversial among many medical professionals.Methods - We conducted a systematic search of the existing literature utilizing different databases, including PubMed/Medline, PSYNDEX, and PsycLit, to research the use and acceptance of CAM among the general population and medical personnel. A special focus on CAM-referring literature was set by limiting the PubMed search to “Complementary Medicineâ€? and adding two other search engines: CAMbase (www.cambase.de) and CAMRESEARCH (www.camresearch.net). These engines were used to reveal publications that at the time of the review were not indexed in PubMed.Results - A total of 16 papers met the scope criteria. Prevalence rates of CAM in each of the included studies were between 5% and 74.8%. We found a higher utilization of homeopathy and acupuncture in German-speaking countries. Excluding any form of spiritual prayer, the data demonstrate that chiropractic manipulation, herbal medicine, massage, and homeopathy were the therapies most commonly used by the general population. We identified sex, age, and education as predictors of CAM utilization: More users were women, middle aged, and more educated. The ailments most often associated with CAM utilization included back pain or pathology, depression, insomnia, severe headache or migraine, and stomach or intestinal illnesses. Medical students were the most critical toward CAM. Compared to students of other professions (ie, nursing students: 44.7%, pharmacy students: 18.2%), medical students reported the least consultation with a CAM practitioner (10%).Conclusions - The present data demonstrate an increase of CAM usage from 1990 through 2006 in all countries investigated. We found geographical differences, as well as differences between the general population and medical personnel.