Qualitative methods, such as the in-depth interview, offer a potentially powerful means of uncovering the complex experiences of patients, carers and clinicians within treatment and decision-making processes. In the context of complementary and alternative medicine (CAM), qualitative interview-based projects allow for subjectivity and complexity within human experience, making them a powerful tool for increasing our knowledge of important processes within CAM. However, qualitative interview-based projects are often poorly designed, carried out and analysed. This article provides a guide for CAM researchers on how to use qualitative interviews to produce meaningful, and methodologically sound, research findings.