The figure of the ‘miracle cure’-peddling quack pretending spectacular properties for worthless tonics is iconic. From their 19th century traveling wagon shows to their 21st century Internet spam scams, hucksters and cranks have been consistently targeted by health authorities as a danger to public health. Yet, in this paper, I argue that this is only one form that the problem of ‘quackery’ has taken in the past two centuries or so in the United Kingdom. Just as Roy Porter showed how the mid-19th century professionalization of medicine gave rise to a ‘quackery with a difference’ as a whole range of new medical movements—homoeopathy, hydropathy, medical botany, mesmerism—actively denounced allopathic or modern medicine, I will suggest that the late 20th century birth of ‘complementary and alternative medicine’ (CAM) has resulted in yet another transformation in quackery. By examining the ways in which regulatory authorities in the UK have come to address what is invariably described as a ‘growing interest in CAM’, I will show how the problem of quackery today is increasingly located in an ethical field of practitioner competency, qualifications, conduct, responsibility and personal professional development, almost (but not quite) regardless of the form of therapy in question.