Update on unethical use of placebos in randomised trials.

The most recent (Fifth) revision of the Declaration of Helsinki, adopted in October 2000 by the World Medical Association (WMA), reinforces the longstanding prohibition against offering placebo instead of effective therapy. The WMA left no doubt that if a beneficial treatment for a condition has already been recognised, it is unethical to offer placebo in place of such treatment to anyone in a study of the same condition. We have previously drawn attention to the discrepancy between the spirit of the Declaration and the common practice of using placebo controls in randomised trials even if effective treatment exists. Despite the mandates of the Declaration of Helsinki and concern from ethicists and scientists, the US Food and Drug Administration (FDA) continues to demand and defend placebo-controlled evidence of efficacy and safety for the development of many new pharmaceuticals, even if effective therapy exists. We suggest that the FDA's arguments defending their practice are insufficient to justify medical research that violates the Declaration of Helsinki.