What is drug safety? We always say that drugs approved by the FDA are safe, and in the public mind that means they do not have any side affects. They are safe. What does it mean legally? The Food, Drug and Cosmetic Act just says that you will do adequate tests by all methods reasonably applicable to show whether or not such a drug is safe for use under such conditions. Notice that it does not tell you what safe for use is. The problem is that no drug, as you well know, is 100% safe. The FDA has long used a working definition of safety: that the benefits outweigh the foreseeable risks for a specific indication in a specific population. and that is what the drug development program needs to show. So in approving a product, the FDA determines, and this is a very simple way of looking at it, that the benefit of the drug exceeds the risk for that population. This is not about just numerical benefit and numerical risk. This evaluation includes weights or values that are assigned to all those risks and the values that are assigned to the benefit. So this very difficult determination is whether the weight of a drug’s benefits is weightier for the population than the weight of the risks. There is another step after a drug is approved—that is, for each patient and each prescriber to make an individual decision based on personal values. You do not have to take a drug. It is not like many other risks that are introduced into society. But for the FDA, determination about drug approval relates to the population.