Bloodletting was the treatment of choice for 2000 years, and doctors and patients believed it was effective because most people recovered after treatment. The learning and teaching of physics is similar to pre-1800 medicine. The pedagogical equivalent of bloodletting is the standard method and has comparable “evidence” of its effectiveness. I will discuss new controlled experiments on the teaching and learning of physics, equivalent to the modern tests of the effectiveness of different medical treatments. These studies show much more effective alternatives to traditional approaches. They are also providing empirically based general principles for learning, particularly learning to think like an expert physicist. This research is starting to shift the teaching and learning of science away from methods based on folklore and opinion to those based on science.