Case management of adult patients with acute poisoning in a university-based emergency department to determine the factors that affect duration of hospital stay was assessed. in this survey, data were obtained for the period between January 1, 1997 and December 31, 2002 at the emergency department (ED). Case analyses of 2229 patients older than 14 years of age were reviewed. Of all patients, 725 (32.5%) were male, 801 (35.9%) were younger than 20, and 540 (24.2%) were older than 30 years. Mean ages of patients were 29.3 +/- 13.2 for the males and 23.8 +/- 9.6 for the females (P < .001). During the study, the greatest number of patients were admitted in May (11.0%). Suicidal poisoning was the observed etiology in the majority of cases (76.4%). Moreover, the mortality rate due to poisoning was 3.9%. Drug ingestion was the most frequent means of poisoning (59.0%), followed by pesticides (19.0%). The rate of poisoning with multiple drugs has declined over time, whereas the rate owing to psychoactive drugs has increased markedly. The mean length of hospital stay was 2.9 +/- 1.8 days and the proportion of patients who stayed for longer than 2 days was 44.3%. The mean length of hospital stay was longer for males, those older than 30 years, those who had been poisoned unintentionally, and for confused and unconscious patients and those who had arrived to ED more than 2 hours after the event. This study suggests that morbidity for adult patients with poisoning varied by sex, age, and season. Length of hospital stay was affected by sex, age, arrival time to ED, mode of transport, severity of poisoning, and type of agent.