Provided are an excipient system and a medical container for an erythrocyte enriched liquid. The excipient system is prepared by adding a hemolysis inhibitor and a surfactant to an erythrocyte storage solution. Herein, the surfactant has an HLB value of 13 or more, and the number of oxyethylene groups at a hydrophilic segment in the molecular structure of the surfactant is 20 or more. The inside of the medical container is filled with the excipient system for an erythrocyte enriched liquid.