Diverse aspects of life and lifestyles, including stigmatised attributes and behaviors are revealed as providers and patients discuss health. In this article, we examine how the stigma associated with substance use issues shapes clinical interactions. We use the theoretical framework of cultural health capital (CHC) to explain how substance use stigma is created, reinforced and sometimes negotiated as providers and patients engage in health interactions. We present two main findings using examples. First, two theoretical concepts – habitus and field – set the social position and expectations of providers and patients in ways that facilitate the stigmatisation of substance use. Second, we found both providers and patients actively exchanged CHC as a key strategy to reduce the negative effects of stigma. In some clinical encounters, patients possessed and activated CHC, providers acknowledged patient's CHC and CHC was successfully exchanged. These interactions were productive and mutually satisfying, even when patients were actively using substances. However, when CHC was not activated, acknowledged and exchanged, stigma was unchallenged and dominated the interaction. The CHC theoretical framework allows us to examine how the stigma process is operationalized and potentially even counteracted in clinical interactions.