Glycyrrhiza glabra L. has a long-standing history in traditional medicine across both Eastern and Western areas. The plant's chemical constituents, such as glycyrrhizin, glycyrrhetic acid, and various flavonoids, offer significant therapeutic potential. Further research could explore its application in modern drug development for the treatment of systemic and non-systemic diseases. In the course of study on the chemical composition of Glycyrrhiza glabra L. in Vietnam, this paper described the extraction and structure evaluation of four compounds, including glabridin (1); 4'-O-methylglabridin (2); glabrol (3); kanzonol Y (4) as well as the melanin inhibition activity of these compounds. The stems of this plant were collected, identified, dried and extracted in different polarity solvents. These substances were isolated from the ethyl acetate extract on the basis of column chromatography combined with thin layer chromatography. Their structures were identified based on spectroscopic evaluation and comparison of corresponding authentic compounds.