One mystery of human nature is why so many patients can't seem to take their pills properly. What's not in question is the size or seriousness of the problem. Half of all folks in the developed world who have a chronic disease don't follow their medication's dosing, scheduling, or other requirements. On top of the estimated 500 million prescriptions a year that go unfilled, another 500 million are not taken correctly. A mountain of studies have confirmed noncompliance's negative effects on everything from drug effectiveness and patient mortality to healthcare costs and pharma revenues. The World Health Organization has stamped nonadherence "a worldwide problem of striking magnitude."