Dextran T500 was used as a supplement in organ culture medium to evaluate its effect on corneal endothelium with disseminated damage. After 1 week of culturing, the control group showed an intact endothelium throughout the entire cornea. However, in the dextran-supplemented group, multiple endothelial necroses were observed in 5 of 10 corneas. Besides, intracytoplasmic vacuoles and granules, deposits on the endothelial surface and widened intercellular spaces were quite numerous. The potential toxicity of dextran to degenerated corneal endothelial cells may be responsible for these findings.