Objective. To characterize early risk factors of moderate/severe hepatotoxicity in a pediatric population with acetaminophen overdose, due to suicide attempt, admitted to a general secondary-level pediatric department. Methods. A retrospective case study of 107 patients, 11 to 15 years old. Results. There was a highly significant relationship between the number of episodes of prehospital vomiting and several elevated hepatologically relevant biochemical parameters, for example, maximum aspartate aminotransferase (P = .0001). The duration of the latency time before initiation of N-acetylcysteine treatment was significantly related to the elevation of several hepatologically relevant biochemical parameters (eg, maximum γ-glutamyl transferase; P = .0001). Patients suffering from illness prior to their suicide attempt had significantly greater elevations of their hepatologically relevant biochemical parameters, for example, maximum alanine aminotransferase (P = .01) levels than healthy patients. Conclusion. By use of risk factors, it is possible to identify pediatric patients at increased risk of moderate/severe hepatotoxicity at an early stage of admission.