Even with the best doctors in the world, and with the most up-to-date medical research, health and wellness continue to confound us. Some medicines and procedures work for one person, and then entirely fail to work for another. Sometimes, these differences in efficacy can be explained. Sometimes, they can't. This can lead to occasional distrust in the medical industry and in doctors—but it shouldn't. Even if conventional medicine doesn't seem to be doing the trick, our understanding is evolving all the time.