Medical marijuana, also known as cannabis, is being sought by patients and survivors to alleviate common symptoms of cancer and its treatments that affect their quality of life. The National Academy of Sciences (2017) reports conclusive or substantial evidence that cannabis is successful in treating chronic cancer pain and chemotherapy-induced nausea and vomiting, moderate evidence that cannabinoids are beneficial for sleep disorders that accompany chronic illnesses, and limited evidence supporting use for appetite stimulation and anxiety. However, due to the fact that cannabis is classified as a Schedule I controlled substance, there is an absence of rigorous, scientific evidence to guide health-care professionals. In addition, the Schedule I designation makes it illegal for health-care professionals in the United States to prescribe, administer, or directly distribute these drugs. Legislation has outpaced research in this area. Therefore, the National Council of State Boards of Nursing (NCSBN) appointed a medical marijuana guideline committee to create guidelines for the nursing care of patients using medical marijuana, marijuana education in nursing programs, and guidelines for advanced practice registered nurses (APRNs) certifying a patient for the use of medical marijuana (The NCSBN Medical Marijuana Guidelines Committee, 2018). Six states/districts authorize APRNs to recommend the use of medical marijuana to patients with qualifying conditions (Kaplan, 2015). As of March 2021, 35 states plus the District of Columbia have authorized the use of medical marijuana (DISA Global Solutions, 2021). Therefore, APRNs will be caring for these patients and need to know the medical, pharmacological, and legal issues surrounding medical cannabis use.