Towards a risk-benefit evaluation of placebos

The notion that placebo can, in certain circumstances, represent a valuable and ethical therapeutic intervention has been repeatedly reconsidered in recent years. This article discusses the possibility of submitting placebos to a conventional risk-benefit evaluation. The benefits of placebos are often not clearly defined. Generally speaking, the potential for benefit is considerable. The risks are similarly ill defined. Both direct and indirect risks are conceivable. On balance, the risk-benefit relation for placebo could be favourable. Under certain conditions, the clinical use of placebos might therefore be a realistic option. In the final analysis, however, our knowledge for a conclusive risk-benefit evaluation of placebo is incomplete.