Advances in the treatment of demented individuals is critically dependent upon experimental administration of new drugs to such people, who, by definition, frequently cannot provide informed consent. Ethical problems associated with studies on demented individuals are therefore of great importance. While there is some similarity to other groups (children, psychotic individuals and patients in coma) there also exist several differences. Obtaining an informed consent from a dementing individual is always problematic. Advance directives are helpful to caregivers and patients should be encouraged, at early stages of the disease, to provide them. Participation in drug studies carries inherent benefits to patients, but at the same time exposes them to risks and discomforts which should be monitored and reviewed more intensively than in studies on cognitively intact individuals. The vulnerability of demented people and their dependence requires special attention by the institutional review board (IRB), unique items to be included in the study protocols and consent forms, etc. Representatives of patients advocacy groups can make important contributions to the IRB, to serve the best interests of the patient and prevent exploitation by the industry as well as by researchers, and honoring the autonomy of the patients. It would be helpful and justified to enable subjects to continue in the study in an open-label design in this situation, once they sign a suitable informed consent. A no-fault insurance could be provided to the patient in this situation.