The arrest of W.N.B.A. star Brittney Griner in Russia after customs officials found vape cartridges with hashish oil she was carrying has caused a diplomatic dust-up—and also prompted debate over whether cannabis is effective for relieving sports injury-related pain, especially in elite athletes. Griner says she was authorized to use medical cannabis in Arizona, and like a growing number of professional athletes, who say they use the drug for pain management. As more and more states legalize weed, professional organizations such as the NFL and the NBA have eased their rules on marijuana use and testing. Nobody should be imprisoned for using pot—anywhere—but the evidence is still out whether cannabis does in fact relieve pain, as the marijuana industry often claims. Most of what we know so far is anecdotal, and research has yet to support or refute any of these personal observations. What’s certain though is that marijuana use poses risks, including harming adolescent brain development, causing cannabis use disorder and respiratory problems, and most worrying for elite athletes—a decrease in athletic performance. Much more research is needed to determine whether cannabis can be useful in pain management, and the best ways to administer the drug safely and effectively.