Patients can experience medication-related harm and hospital readmission because they do not understand or adhere to post-hospital medication instructions. Increasing patient medication literacy and, in turn, participation in medication conversations could be a solution. The purposes of this study were to co-design and test an intervention to enhance patient participation in hospital discharge medication communication. In terms of methods, co-design, a collaborative approach where stakeholders design solutions to problems, was used to develop a prototype medication communication intervention. First, our consumer and healthcare professional stakeholders generated intervention ideas. Next, inpatients, opinion leaders, and academic researchers collaborated to determine the most pertinent and feasible intervention ideas. Finally, the prototype intervention was shown to six intended end-users (i.e. hospital patients) who underwent usability interviews and completed the Theoretical Framework of Acceptability questionnaire. The final intervention comprised of a suite of three websites: (i) a medication search engine; (ii) resources to help patients manage their medications once home; and (iii) a question builder tool. The intervention has been tested with intended end-users and results of the Theoretical Framework of Acceptability questionnaire have shown that the intervention is acceptable. Identified usability issues have been addressed. In conclusion, this co-designed intervention provides patients with trustworthy resources that can help them to understand medication information and ask medication-related questions, thus promoting medication literacy and patient participation. In turn, this intervention could enhance patients' medication self-efficacy and healthcare utilization. Using a co-design approach ensured authentic consumer and other stakeholder engagement, while allowing opinion leaders and researchers to ensure that a feasible intervention was developed.