Provided is a drug or method for treating or preventing a condition, disorder, or disease of the corneal endothelium caused by transforming growth factor-ß (TGF-ß) signals, mitochondrial abnormalities, and/or endoplasmic reticulum (ER) associated stress in corneal endothelial cells, using p38MAP kinase inhibitors. The present invention provides a drug which includes p38MAP kinase inhibitors, and which is for treating or preventing a condition, disorder, or disease of the corneal endothelium caused by TGF-ß signals and/or mitochondrial abnormalities in corneal endothelial cells. In the preferred embodiment, the condition, disorder, or disease of the corneal endothelium is Fuchs corneal endothelial dystrophy.
