Those following the Olympics this year may have noticed Michael Phelps sporting circular bruises all over his body. That’s because Phelps, like many Olympic athletes, won’t go after their medals without going after their cups. The growing fad of cupping is an ancient practice in which cups are placed all over the body and skin is suctioned inside the cup, bursting blood vessels and creating circular bruises. The claim is that cupping releases toxins and heals muscle tissue, among a number of other alleged health benefits, none of which can be backed up by scientific evidence.    Dr. David Gorski is a surgical oncologist, blogger, and advocate for evidence-based reasoning. He joins us today to discuss the latest Olympic pseudoscience fads and what it is about them that makes them pseudoscience. He gives his take on why alt-med practices like cupping are so appealing to people, and the best ways to go about persuading people out of them.