 Our study examined the effectiveness of cost containment policies for drug prices and quantities in Korea during the 2010s. We found that these policies led to significant price reductions and incentives for more efficient drug prescriptions, resulting in an immediate decrease in monthly drug expenditures in clinics. However, this effect was not sustained over the long term, as the most expensive clinics continued to show the highest rates of increase in drug costs. To maximize the effectiveness of future policy interventions, it may be beneficial to focus on high spending providers. This article was authored by Woo-Hin Kim, Hee-Joo Koo, Hee-Jae Lee, and others.