Purpose: The Korean government has tried to decrease the suicide death rate over the last decade. Suicide attempts, particularly non-fatal attempts, are the most powerful known risk factor for a completed suicide. An analysis of suicide attempt methods will help establish the effective preventive action of suicide. Fit prevention according to the method of suicide attempt may decrease the incidence of suicide death. Self-poisoning is suggested as a major method of both suicide attempts and suicide death. The aim of this study was to determine if a self-poisoning patient is a suitable target for the prevention of the suicide. Methods: This was retrospective analysis of a prospective cohort, which included patients who presented to the emergency department (ED) after a self-harm or suicide attempt from Jan 2013 to Dec 2017. The proportion of methods in suicide attempts, psychological consultation, and fatality according to the suicide attempt method were analyzed. The types of poison were also analyzed. Results: Poisoning was the most common method of suicide attempts (52.1%). The rate of psychological consultations were 18.8% for all patients and 29.1% for poison patients (p<0.001). The rate of mortality in poisoning was 0.6%. Psychological consultation was performed more frequently in admission cases than discharged cases. The most common materials of poisons was psychological medicines and sedatives that had been prescribed at clinics or hospital. Conclusion: Self-poisoning is a major method of suicide attempt with a high rate of psychiatric consultation, low mortality rate, versus others methods. The prevention of suicide death for suicide attempts may focus on self-poisoning, which is the major method of suicide attempts. A suitable aftercare program for self-poisoning may be an effective method for preventing suicide if an early diagnosis and management of psychiatric disorders through psychiatric consultation can be made, and early connection to social prevention program for non-fatal patients are possible.