While many drugs are used exclusively for medical reasons, and others are used solely for recreational enjoyment, some drugs are commonly used for both purposes. For example, cannabis, opioids, and stimulants are unique in many ways, but they share the fact that they are regularly consumed both medicinally and recreationally (Dinnin Huff, Humphreys, and Wilner 2021; Drazdowski 2016). However, it is not clear how the existence of recreational markets for substances affects moral judgments of their medical use. The current work shows that using a drug for medical reasons is viewed as less morally acceptable if other consumers use the same drug for recreational enjoyment. This effect emerges due to observers inferring that medical users are less purely motivated by medical need. Accordingly, the negative effect of recreational drug use on moral judgments of its medical use is mitigated when patients do not have alternative treatment options. These findings have implications for patient stigmatization, drug marketing and lobbying, and for policy and legislation designed to regulate the use of medical drugs with recreational benefits.