Eight research protocols which had previously been approved by Ethical Research Committees (ERCs) were reviewed in simulated review committees set up during a symposium on medical ethics. Only three protocols were considered to provide fully adequate information to allow ethical review and only one protocol was thought to provide sufficient guarantees on the ethical issues raised by the proposed research. For five other protocols additional safeguards were considered necessary, in particular covering the problem of informed consent. Two protocols were considered (...) to raise unresolvable ethical issues. This artificial exercise does not establish that review by ERCs is ineffective. It does highlight the lack of objective criteria in ethical review. Peer review by exchange of protocols between ERCs could assist in increasing the consistency in the application of ethical standards. (shrink)