Abstract Background People report using cannabis as a substitute for prescription medications but may be doing so without the knowledge of their primary health care providers (PCPs). This lack of integration creates serious concerns, e.g., using cannabis to treat medical conditions that have established treatment options. Methods We conducted an anonymous, cross-sectional online survey among patrons of a medical cannabis dispensary in Michigan (n = 275) to examine aspects of their relationship with their PCP and their perceptions of PCP knowledge related to cannabis. Results Overall, 64% of participants initiated medical cannabis use based on their own experiences vs. 24% citing advice from their PCP....