Purpose: The Korean government approved selected nonprescription drugs (Over-The-Counter drug; OTC drug) to be distributed in convenience stores from 15. Nov. 2012. This study examined the changes in the incidence and the clinical outcome of acute pharmaceutical drug poisoning after the deregulation of OTC drug sales. Methods: This study analyzed the data of Emergency Department based Injury In-depth Injury Surveillance (EDIIS), Korea Centers for Disease Control and Prevention, from 2011 to 2014. The following items were examined: age, gender, intention, alcohol association, pharmaceutical drugs resulting acute poisoning, the clinical outcomes in emergency department, and the admission rate of intensive care unit (ICU). This is a retrospective cross section observational study. Results: A total of 10,162 patients were subject to pharmaceutical drug poisoning. Acute poisoning by acetaminophen and other drugs were 1,015 (10.0%) and 9,147 (90.0%) patients, respectively. After the deregulation of OTC drug sales, acute poisoning by other drugs increased from 4,385 to 4,762 patients but acute poisoning by acetaminophen decreased from 538 to 477 patients (p<0.05). The rate of admission of acetaminophen poisoning increased from 36.1% (194/538) to 46.8% (223/477). The admission rate to the ICU by acetaminophen poisoning increased from 4.6% (25/538) to 11.3% (54/477) after the deregulation of OTC drug sales (p<0.05). Conclusion: Since the deregulation of OTC drugs sales, pharmaceutical drug poisoning has increased but acetaminophen poisoning has decreased. The rate of hospitalization and ICU admission by pharmaceutical drug poisoning with or without acetaminophen has also increased.