Background: The aim of this retrospective study was to analyse the characteristics of acute adult poisoning cases admitted to a university hospital in Istanbul, Turkey. Patients and methods: All cases admitted to the Emergency Unit of the Istanbul University Cerrahpas, a Medical Faculty Hospital, between January 2001 and December 2001, were included in this study. We analysed the clinical charts for aetiological and demographical characteristics of the acutely poisoned patients. Results: There were 284 poisoning cases ( 207 females and 77 males) among 11 834 patients admitted to the Emergency Unit. This was 2.4% of all emergency admissions. The female-to-male ratio was 3: 1. The mean age was 27 +/- 12 years ( age range 15 - 87) and the majority of the patients (73.94%) were below the age of 30 years. The median age was 24 years. Medicinal drugs were the major cause (69.37%) of the cases, followed by inhalation of gases (14.44%), alcohol (5.99%), alcohol together with illicit drugs (4.23%), food (3.17%), corrosives (1.76%) and pesticides (1.06%). The route of administration was as follows: 84.51% orally, 14.44% by inhalation and 1.06% by intravenous injection. Seventy-one per cent of acute poisonings were self-inflicted and 88% occurred at home. The most frequently involved medicinal drugs were antidepressants and analgesics. In 32.04% of cases, there was more than one medicinal drug responsible for the poisoning. The seasonal distribution in poisoning patients suggested a peak in summer (31.7% of presentations) and winter (30.9%) and lower numbers in spring (22.9%) and autumn (14.5%). The follow-up period of the patients were 1 - 12 hours for 42 cases (15%), 13 - 24 hours for 134 cases (47%) and more than 24 hours for 108 cases (38%). Two of the 284 cases with acute poisonings were fatal. This was a university hospital-based study, so these results may not be representative of the general population. Despite this drawback, these data still provide important information about the characteristics of poisoning in the largest city of the country.