ethics in clinical trial

background: clinical trial is the standard method to assess efficacy of a medical intervention. because of its experimental nature, meaning that subjects are exposed to an intervention with uncertain outcome and according to historical evidences of criminal researches, clinical trial is of something of a lightning rod for ethical concerns. ethical issues surrounding clinical trials are very pervasive and in many respects, they are as important as the methodological issues. patients place a great deal of trust in clinical investigators and often participate in trial when the chance of personal benefit is low. the clinical investigators must continue to earn this trust by demon storable commitment to ethical standards. methods: in this article after reviewing the appropriateness and necessity of clinical trial and its required methodological characteristics, ethical issues consisting importance of protocol, informed consent, study on vulnerable subjects, compensation, conflict of interest and responsibility of ethical committees in evaluation of clinical trial will be discussed. conclusion: to assess efficacy of a medical intervention, clinical trial is ethicly not only inevitable but also necessary. however it doesn't reduce necessity of attention to the participants rights.