In geriatric departments, physicians are faced with two difficulties, first the increasing number of infections caused by multiresistant bacteria, especially extended spectrum β-lactamase (ESBL) producing enterobacteria strains and second, the poor venous access frequently encountered in elderly population. Giving antibiotics subcutaneously would be an interesting alternative, all the more as intramuscular injection is contraindicated in case the of anticoagulant therapy. Unfortunately, few data are available about subcutaneous (SC) administration. Ertapenem is a recent long-acting parenteral carbapenem indicated especially in the treatment of ESBL infection. Its subcutaneously administration has been tested in several studies in Intensive Care Units (ICU) and internal medicine wards with promising results regarding clinical and pharmacokinetics data.