The pharmacological properties of the conjugate of penta-O-acetylglycyrrhizic acid with methionine methyl ester were studied. The antiinflammatory (AI) activity was estimated using mouse and rat inflammation models induced by formalin, thermal action, Difco agar, trypsin, histamine, and bradykinin compared with glycyrrhizic acid (I), butadione, and prednisolone. It was found that this compound has distinct AI activity that exceeds the activity of I. The AI activity of the conjugate was combined with high antiulcer (AU) activity that exceeded that of I. The conjugate healed both acute (histamine and serotonin) and chronic (reserpine and acetic acid) ulcers of rat stomach mucous lining and had low toxicity.