Statins inhibit the synthesis of cholesterol and decrease levels of low-density lipoproteins, which many believe are atherogenic. Since their development in 1987, statins have become the single most prescribed class of drugs in medicine, and well over 100 million people worldwide take them daily. Here, Dr. Malcolm Kendrick discusses some of the controversies surrounding the popular drugs and explains the evidence that suggests their benefits may be overstated and their adverse effects significantly underestimated.