Due to the chronic lack of beds in hospitals, patients are often hospitalized in other departments (outlier patients), with a responsible physician working in another department. This causes increased thromboembolics risks, nosocomial infections, falls and delirium in the elderly, morbidity and mortality. Outlier patients, compared to standard patients, stay longer in the emergency department and their discharge documents are available later. Outlying is used daily in the CHUV hospital and new strategies are elaborated to manage patient flow, especially during the flu epidemic. The purpose of this article is to review the literature on this subject.