It is intended to provide an organ function maintaining or ameliorating solution, which is effective for suppressing the depression of an organ provided for transplantation and an organ preservation method using the organ function maintaining or ameliorating solution. The present invention relates to an organ function maintaining or ameliorating solution for maintaining or ameliorating the functions of an organ provided for organ transplantation, comprising a pharmacologically active substance comprising glycyrrhizic acid, glycyrrhetinic acid or a pharmacologically acceptable salt or derivative thereof in an organ preservation solution. The present invention also relates to a method of preserving an organ for organ transplantation comprising perfusing the organ function maintaining or ameliorating solution to the organ isolated from the donor to cause ischemia and immersing the organ in the organ function maintaining or ameliorating solution during the time until the organ is transplanted into a recipient.