The well-conducted randomised controlled trial (RCT) is widely regarded as providing the most unbiased estimate of the true efficacy of interventions. Ethical concerns have been raised by professionals and lay people since the advent of the RCT. These largely involve the issues of whether true equipoise (a state of uncertainty where a person believes it is equally likely that either of two treatment options is better), which forms (or should form) the basis for conducting an RCT, is possible in clinical research; the use of placebo controls, especially where effective treatments exist ; and the problem of how informed, voluntary and competent the consent obtained for such trials really is, especially in vulnerable populations and when research is conducted in settings of routine clinical care. More recent concerns pertain to the ethics of conducting clinical trials in the developing world. An additional issue is that of the ethics of conducting clinical trials in resource-poor settings that appear to be purely for the regulatory purposes of foreign agencies.