The ideal of shared decision making starts from the assumption that physicians and patients are able to take a joint decision as to what is the best treatment. However, since medical consultations are to be viewed as discussions between an expert and a layman, in practice it will often be the case that the patient has to rely on the physician’s expertise. In this article we examine the extent to which the Dutch laws, guidelines and professional conventions within the medical domain positively influence the quality of the process of shared decision making, even in cases where the physician makes use of an argument from expert opinion. To this end, we will chart some of the most important institutional safeguards for the quality of medical decisions and analyze how these safeguards relate to the critical questions associated with the argument scheme of argumentation from expert opinion.