CHP/PCOR fellow Randall S. Stafford provides comment for a March 3 San Francisco Chronicle article on what it means -- and doesn't mean -- when a drug wins Food and Drug Administration approval. Stafford says the recent cases of drugs being taken off the market due to previously unknown risks, illustrate the limitations of FDA approval, and show that physicians should be more conservative about prescribing new drugs for their patients. The article also cites Randall's recently published study finding that the vast majority of people who were prescribed COX-2 inhibitors didn't need the medications and could have done just as well on older, cheaper drugs.