It is to provide a method of washing an adherentcell, capable of effectively suppressing cell death due toproteolytic enzyme treatment for detaching the adherentcell from a culture vessel and subsequent cell treatment；a cell-washing solution used for the washing method； amethod of producing a cell suspension for transplantationusing the cell-washing solution； and a kit comprising thecell-washing solution. Trehalose or its derivative or asalt thereof is added to a physiological aqueous solutionto prepare a cell-washing solution containing trehalose orits derivative or a salt thereof as an active ingredient.The cell-washing solution can be used to wash an adherentcell before detaching the adherent cell from a culturevessel by proteolytic enzyme treatment to suppress(inhibit) cell death (apoptosis or the like) due to theproteolytic enzyme treatment. The concentration oftrehalose applied to the cell-washing solution may be aconcentration capable of suppressing (inhibiting) the celldeath (apoptosis or the like) due to the proteolyticenzyme treatment, and is typically 0.1 to 20 (w/v)%,preferably 1 to 15 (w/v)%, more preferably 1.0 to 7.0(w/v)%, still more preferably 3 to 5.0 (w/v)%.
