Although medical and pharmacy curricula and journals are rich with information about drugs and treatment of specific diseases, there is a paucity of education on ways to become effective lifetime prescribers. Two recent reports from the Association of American Medical Colleges (AAMC) lamented the current state of pharmacology teaching1 and the disturbing extent of pharmaceutical industry influence at all stages of medical education.2 Given the well-documented prevalence of medication-related harm and inappropriate prescribing,3,4 such educational reform is necessary but not sufficient to ensure that patients are optimally treated. Beyond improved training in pharmacology and minimization of unbalanced industry-sponsored education, trainees need guiding principles to inform their thinking about pharmacotherapy to help them become more careful, cautious, evidence-based prescribers.