The pool of misinformation fed to the public as fact has diluted the perception of marijuana since it was originally made illegal. In the last 10-15 years we have made great strides in researching marijuana in several fields, even with the extremely limited access to it. Recently, even the National Cancer Institute has recognized marijuana as a cancer-fighting medicine, which supports new research suggesting marijuana users could be 45% less likely to develop bladder cancer. The study was done back in the early 2000's with over 80,000 men, and after an 11-year follow-up patients who smoked only marijuana (and not tobacco) held significantly less risk of developing bladder cancer.
The study, which was conducted via questionnaire and undertaken by Kaiser Permanente of California, showed that users who smoked marijuana were 45% less likely to develop bladder cancer than those who didn't in a follow-up after 11 years. As specifically noted in a presentation in 2013 by Dr. Anil Thomas, a urologist at the South California Permanente Medical Group, 0.4% of all men who had not used cannabis reported that they had developed bladder cancer, while 0.3% of cannabis users reported developing bladder cancer. The difference was described as "statistically significant."