In the United States, 58% of the country’s states have a medical cannabis law, allowing physicians to certify patients for state-specific medical conditions. The increasing mainstream acceptance of this complex herb as medicine has jumped far ahead of the current scientific evidence regarding efficacy, dosing, drug interactions, and certain aspects of safety. This Virtual Special Issue on Medical Cannabis seeks original research as well as articles on surveys, historical perspectives, national and international comparisons of treatment guidelines, policy work, and other relevant contributions.