Professional boundaries are central to professionalism. Failure to maintain sexual and emotional boundaries can cause patients significant and enduring harm. Although prevalence data is poor, evidence from complaints shows that boundary abuses do occur in the CAM sector. Concerns are heightened by contextual, regulatory and therapeutic aspects of CAM relationships. This article argues that learning about sexual boundaries should be a specific element of CAM training and makes recommendations as to how to implement this key element of patient safety.