As the main medications consumers, elderly persons are estimated to represent up to 30% of the European population in 2050. Paradoxically there is a considerable lack of information about drug prescription in older persons, which is compromising the quality of treatments, and leaving to physicians the considerable responsibility of improvised prescriptions, which are potentially either dangerous or ineffective. In fact, the geriatric population is either excluded from clinical trials or represented by relatively healthy elderly persons who do not accurately represent real world patients. Despite repeated demonstrations of the need to include frail elderly persons in clinical trials in the medical literature, European law only offers disappointing responses to the problem. The frequent decline in older persons' cognitive capacities makes the task even more difficult (cognitive frailty, early dementia like Alzheimer's disease or psychiatric disorders). Many older persons have reduced decision making capacity without benefiting from legal protection yet. Surprisingly, ethics guidelines as well as European law are not very sensitive to the phases before legal incompetence, and do not consider alternative ways to obtain informed consent as suggested in medical and ethical literature. Although these questions fall under national competencies, the issue is common to Europe and solutions will necessarily have to go beyond state borders. Involving the European legislator is essential in order to at least act as an incentive for a better inclusion of frail elderly persons in biomedical research, and for a better promotion of their autonomy.