The scientific understanding of Korean medicine theory remains largely unknown, since there is a lack of proper methods to investigate its complex and unique characteristics. Here, we introduce a drug-centered approach, a novel method to investigate Korean medicine theory by analyzing the mechanisms of herbal medicines. This method can be effectively conducted by employing network pharmacology that can analyze the systems-level mechanisms of herbal medicines on a large scale. Firstly, we introduce the method of network pharmacology that are applied to analyze the mechanisms of herbal medicines in a step-by-step manner. Then, we show how the drug-centered approach employing network pharmacology can be applied to investigate Korean medicine theory by describing studies that identify the biological correlates of the cold-hot nature of herbs, spleen qi deficiency syndrome, or Sasang constitution. Finally, we discuss the limitations and future directions of the proposed approach in two aspects: The methods of network pharmacology for a drug-centered approach and the process of inferring Korean medicine theory through it. We believe that a drug-centered approach employing network pharmacology will provide an advanced scientific understanding of Korean medicine theory and contribute to its development by generating biologically plausible hypothesis.