OBJECTIVES: To study the nature of CAM use in primary care attenders, the involvement of their NHS healthcare professionals in their CAM care and differences in characteristics between CAM users and non-users. DESIGN: Postal questionnaire for primary care attenders and analysis of practice leaflets. SETTING: Six Scottish GP practices with a range of practice size, CAM provision within practice, deprivation and rurality. RESULTS: Five hundred and fourteen primary care attenders described 1194 incidences of CAM use and gave details about their main therapy. 37% had contact with a practitioner, the rest mainly self-prescribed. The perceived effectiveness of CAM was high. Patients used CAM for a variety of health problems, mainly as an adjuvant to orthodox medicine rather than an alternative. The involvement of the NHS in CAM delivery was small but there is a significant role to ensure patient safety, especially regarding herb-drug interactions. Disclosure rate of CAM use was low. CAM offered options in areas where the provision in the NHS is difficult, including musculo-skeletal and mental health problems. Provision of CAM by the GP is associated with higher CAM use in primary care attenders. CONCLUSIONS: It is recommended that healthcare professionals include patients' use of CAM in history taking and clinical decision making.