Abstract Objective To determine the effects of medical cannabinoids on pain, spasticity, and nausea and vomiting, and to identify adverse events. Data sources MEDLINE, the Cochrane Database, and the references of included studies were searched. Study selection Systematic reviews with 2 or more randomized controlled trials (RCTs) that focused on medical cannabinoids for pain, spasticity, or nausea and vomiting were included. For adverse events, any meta-analysis for the conditions listed or of adverse events of cannabinoids was included. Synthesis From 1085 articles, 31 relevant systematic reviews were identified including 23 for pain, 5 for spasticity, 6 for nausea and vomiting, and 12 for adverse events. Meta-analysis of 15...