What is medicinal cannabis?

As New Zealand considers cannabis legal reform, we ask: what exactly is medicinal cannabis, and why does this matter? Cannabis is not a single entity but comes in diverse forms with various active ingredients. This contrasts with the legal and pharmaceutical definitions of medicines, with wide-ranging implications for quality control, prescriber practice and the assessment of clinical evidence. We argue that what is considered a medicine in the legal and pharmaceutical sense should not be changed in an ad hoc way to accommodate cannabis, but that cannabis products should be held to the same standards as other medicines.