The researchers found that advanced cancer patients who used medical cannabis had positive effects. “Ninety-three patients (51.5%) received at least one prescription from a New York licensed marijuana dispensary while 72 (39.13%) were certified but never obtained any medical marijuana,” they wrote. “For patients who took at least one dose of medical marijuana, 48.14% experienced an improvement in pain, 44.95% used fewer opioids, and 85.11%   had an improvement in at least one symptom. Adverse effects were low at 3.72%.,” says the study.