It can be hard to know which medical evidence to believe. One day you may hear that drinking alcohol is good for your heart. The next day you may hear that alcohol makes it more likely that you'll get breast cancer. And your friend may swear that a treatment you've never heard of saved his mother's life.

All medical research is not created equal. Some studies are more reliable than others. So we've put together some guides to help you weigh the evidence and work with your doctor to choose the treatment that is best for you.