Longitudinal double vital staining with 1% rose bengal (RB) and 1% fluorescein (Flu) has been carried out on 33 eyes subjected to penetrating corneal transplantation. At the conclusion of the operation pronounced desiccation of both donor's and recipient's epithelium was seen in a scant 50%, but abrasion in only 8%. the desiccation subsided during the first post-operative day, but the donor's epithelium was rejected in the majority (91%). Healing started on the third day, manifesting itself by Flu-punctate whorl-shaped epithelium invading or gliding across the wound. By the fifth day nearly complete healing had occurred. In 9% no renewal of epithelium was noticed. Subsequent control examinations revealed loose sutures (RB-stained mucous adhesions), evanescent cicatricial defects, and open suture canals (Flu). Graft rejection occurred in 8 cases. In 5 of these, well-defined massive peripheral staining of donor epithelium was seen (RB most widespread and sharply outlined), and in the remaining 3, uncharacteristic, diffuse, punctate staining.