Abstract : Elderly patients, having various chronic diseases, are generally exposed to polypharmacy that may lead to potential adverse events. The latter may be explained by pharmacokinetic and pharmacodynamic particularities that render elderly individuals more vulnerable when exposed to certain medications. Recruitment of elderly patients in clinical trials is often limited, so that it is not always easy to determine the real benefit/risk ratio of pharmacotherapy in this population. Obviously, iatrogenicity is quite frequent. Therefore, in front of unexplained alterations of health status in an elderly individual, the physician should consider the possibility of a drug adverse effect. Because of this situation, the physician should envisage a reasonable drug prescription in an elderly patient. Especially, not only the initiation of drug therapy should be carefully analyzed, but also the opportunity to eventually stop a medication that may be useless or even dangerous. Rather polypharmacy per se, it is the inappropriate prescription that should be avoided in the elderly.