Objectives : Decoction, in Korean Medicine, is a pharmacological method of extraction, by boiling, of dissolved chemicals, or herbal prescriptions, which may include stems, roots, bark and rhizomes. Decoctions differ from most teas, infusions, in that they are usually boiled. This study was performed to compare the difference of water decoctions extracted by different decoction extractor and extraction time and to analyze the reason of decoctions extracted by each decoction extractor have different taste. Methods : With water decoction samples by Pressure extractor, Non-pressure extractor and Ultrasonic waves merge extractor for 1 hr, 2 hr and 3 hr were investigated the yield and the concentration of hesperidin and glycyrrhizin by HPLC/DAD system in Pyungwi-san decoction. Results : The samples of each extractor were gradually increased the yield and the concentration of hesperidin and glycyrrhizin. The HPLC pattern of samples is similar. The yield and the concentration of hesperidin and glycyrrhizin of Ultrasonic waves merge extractor was most highest of the three. The rate of increase of the yield and the hesperidin concentration of between 1 hr and 2 hr in Pressure extractor was the most highest of the three. But the concentration of glycyrrhizin in Pressure extractor was relatively similar to Non-pressure extractor. Conclusions : The yield and the concentration of reference compounds in Pyungwi-san water decoction was influenced by extracting method and extracting time. For scientific movement and standardization of extracting medicinal herbs method need to study of extractor validation and to study in vitro and in vivo.