There is conclusive evidence that marijuana is good for treating chronic pain. This is one of the most common reasons cited for marijuana’s medical use — particularly in light of the opioid painkiller epidemic, which has spawned in part as patients turn to opioids to try to treat debilitating pain. The report concludes that marijuana can treat chronic pain. And that may allow it to substitute more dangerous, deadlier opioid painkillers. The report also found conclusive evidence that marijuana is effective for treating chemotherapy-induced nausea and vomiting. Coupled with the findings on pain, this suggests that marijuana really is a potent treatment for cancer patients in particular, who can suffer from debilitating pain and severe nausea as a result of their illness