The very long and expensive process of new drug research and development might suggest to observers that the efficacy standard for drugs is elevated and substantial, but this is not the case. Under the U.S. Federal Food, Drug, and Co smetic Act, new drug approval merely requires that there be “substantial evidence that the drug will have the effect it purports or is represented to have.” While the evidence of effectiveness must therefore be substantial, the efficacy attested to by that evidence need not surpass any particular threshold (other than zero), thus allowing drugs with de minimis efficacy to be approved and sold at market rates. No other concept, principal, or standard applied during the approval process or after changes this result. The “gold standard,” which includes the elements of blinding, randomiza tion, and placebo control, is described in but not required by the drug statute, and in any event addresses various problems related to bias rather than magnitude of efficacy. Similarly, the concept of “statistical significance,” which constitutes an essential element of modern research protocols, addresses the problem of certainty, not degree, of efficacy. The statutory requirement of “clinical significance,” far from ensuring “substantial efficacy,” demands no more than that there be statistical significance in a human study (as opposed to, for example, an animal study). Rather than specifying a fixed level of efficacy or even a flexible standard of efficacy that a drug must possess, the U.S. drug approval framework thus fully delegates to drug companies and to the free market the determination of what level of efficacy is acceptable. The critical implication is that the public (and physicians and insurers) should not rely on the fact of FDA approval as an indication th at medicines, including new and very highly priced ones, possess efficacy that is meaningfully greater than no efficacy at all.