Purpose: Intentional poisoning is a major public health issue in many parts of the world. This study was conducted to provide details regarding the epidemiology of intentional poisoning in a metropolitan emergency department and to identify the changing patterns and epidemiology of poisoning. Methods: A retrospective study was conducted to evaluate intentional poisoning of patients who visited the emergency department in a tertiary teaching hospital between 2001 and 2015. All intentional poisoning-related emergency department visits over three five year periods (2001-2005 (P1), 2006-2010 (P2) and 2011-2015 (P3)) were reviewed to investigate trends in intentional poisoning patients. Information regarding patient sex, age, time from episode to admission, psychiatric history, type of intoxicants, alcohol co-ingestion, gastric lavage, charcoal administration, any previous suicide attempts, need for hospitalization and death before discharge was reviewed. Results: A total of 1269 patients were enrolled in this study. The number of patients admitted during each period was P1=515, P2=439 and P3=315. Comparison of the three groups revealed significant differences according to age (p<0.001), psychiatric history (p<0.001), alcohol co-ingestion (p=0.013), gastric lavage (p<0.001), charcoal administration (p<0.001), need for hospitalization (p=0.044), repeated attempt (p<0.001) and type of intoxicants (p<0.001). Conclusion: The average age of intentional poisoning patients has increased. While the use of sedatives and multiple drugs increased, the use of pesticides and the antihistamine decreased.