Placebo-controlled trials and the Declaration of Helsinki.

A revised version of the Declaration of Helsinki, issued in October, 2000, remains a vital expression of medical ethics, and deserves unanimous support. A strict interpretation of the declaration seems to rule out clinical trials that use a placebo control group whenever licensed therapeutic methods already exist, preferring active controls. Although the efficacy of some new medicines can be satisfactorily established without the use of a placebo, for others the judicious use of placebo remains essential to establish their effectiveness.