Abstract Background Cancer patients experience multiple symptoms throughout their illness, and some report benefit from the use of cannabis. There are concerns that many patients are accessing products inappropriate for their situation and potentially putting themselves at risk. In the present study, we aimed to capture the prevalence of cannabis use among cancer patients at BC Cancer before recreational legalization in Canada and to identify the reasons that patients take cannabis, the various routes of administration they use, and the reasons that prior users stopped. Methods Patients were eligible if, on the selected study day (15 August 2018), they were scheduled for an appointment...