With poor (low) solubility in the aquatic environment, highly toxic drugs (aspirin, doxorubicin, daunorubicin, sulfonamides and others), a low level of glycyrrhizic acid (HA) leads to a decrease in the toxicity of drugs and increases their biological activity due to poor solubility in water. The stability constants (stability) and the value of the Gibbs energy of the synthesized supramolecular complex have been calculated, theoretical and experimental research methods were used to determine the conditions for obtaining supramolecular complexes of glycyrrhizic acid and thiourea. These researches were carried out as part of joint work to study the effect of the toxicity of medicines on a living organism, under an interuniversity program between Andijan State University and the Tashkent Pharmaceutical Institute of the Republic of Uzbekistan. The aim of the research is to determine the stability constant (stability) of the synthesized supramolecular complex of the monoammonium salt of glycyrrhizic acid (MASHA) with thiourea and the value of the Gibbs energy. To determine the structure and composition of the resulting supramolecular complex of MASHA with thiourea, UV and IR spectroscopy and the isomolar series method were used.