Physicians commonly recommend ?placebo treatments?, which are not believed to have specific efficacy for the patient's condition. Motivations for placebo treatments include complying with patient expectations and promoting a placebo effect. In this article, we focus on two key empirical questions that must be addressed in order to assess the ethical legitimacy of placebo treatments in clinical practice: 1) do placebo treatments have the potential to produce clinically significant benefit? and 2) can placebo treatments be effective in promoting a therapeutic (...) placebo response without the use of deception? We examine evidence from clinical trials and laboratory experiments bearing on these two questions. The conclusion is reached that based on currently available evidence, it is premature to judge whether placebo treatments are ethically justifiable, with the possible exception of acupuncture for pain relief. (shrink)