In this study the role that contraction plays in the healing of gastric wounds is explored experimentally. Superficial gastric mucosal defects made in the columnar part of rat stomachs were found to close rapidly, compared to defects carried down into the muscle layer. The collagen was packed tightly at the edges of the defects and no other factors appeared to have played a part in the closure. It is surmised that the decrease in size of the defect is due to fibroblastic activity causing contraction. It would seem likely that the myofibroblast, as described by other investigators, would be the unique cell causing this action. Further studies are required to confirm or refute this hypothesis.