The notion of ‘addiction’ appears to present profound and intractable difficulties for contemporary medicine. Using the problem of alcohol addiction as a mediating example, this paper examines some of the sources of these difficulties, and relates these to critiques of the medicalisation of the addictions. It is argued that the difficulty that medicine faces in the case of the ‘addict’ is not that addiction to alcohol has been medicalised, but rather that over a period of two centuries the medicalising project has been only partially successful. Thus medical knowledge and practice have taken as their focus the problem of susceptibility, but made little headway in the domain of conceptualising recovery. In this context, the clinician is forced to divide the susceptible from the culpable in the diagnosis of addiction, and to explain this in terms of the potential for moral self-actualisation on the part of the addict.