evidence: Cannabis is an ancient plant that has been used for rituals and medicine for 5,000 years. People with cancer have turned to cannabis — better known as weed or marijuana — to relieve effects of both the illness and the treatment. Because of its ever-changing legal status, studies have been limited. So what do we really know about its safety and effectiveness? [...] What does marijuana do for cancer symptoms and treatment side effects? [...] To learn more about cannabis and cancer, tune in to this episode of Cancer Straight Talk from MSK.