There are two kinds of patients who leave emergency departments prematurely without completing the ED procedures: informed discharges (AADs) and uninformed discharges. Informed discharges include non-critical AADs and critical AADs; uninformed discharge include patients LWBS (leaving without being seen) and patients who escape. Foreign researche has indicated that the latter kind of patient has some particular personal characteristics which are triggered in special medical situation, which means that patient traits and the circumstances they find themselves in can lead to this behavior. There are quite a few foreign reports which mention no-bed-AADs and transfer-AADs, but there are few reports for Taiwan. As the medical circumstances of Taiwan are not totally similar to foreign situations, we can not refer to theirs experiences to guide our practice, and we need more of our own studies which focus on these issues.