Licorice, Glycyrrhiza glabra Linn., is one of herbal medicines widely used for various purposes, including as a sweetener and for gastric ulcer treatment. However, environmental destruction due to the harvesting of wild licorice is becoming a serious problem. We cultured licorice in a hydroponic system to examine the relation between the concentration of nutritional solution applied and glycyrrhizin content to determine the optimal nutrient solution concentration for commercial licorice production. Licorice growth and glycyrrhizin content in the root reached the highest values when the plants received nutrient solution approximately equivalent to a quarter unit of Hoagland solution. The results also indicated that the glycyrrhizin content does not correlate with the concentration of nutrient solution applied and/or inorganic contents absorbed, i.e., licorice may absorb large amounts of nutrient solution but the glycyrrhizin content may not increase.