In this research, the preparation of licorice extract and the biosynthesis of manganese oxide in the treatment of stomach cancer were investigated by examining the cytotoxicity of the stomach cancer line. The structural properties of manganese oxide were also studied through X-ray examination, scanning electron microscope (SEM), and infrared spectroscopy, where it was found that manganese oxide is polycrystalline, and the average grain size is 62.571 nm, but by SEM, the grain size is 93.49-47.74 nm.