This study was conducted to determine the contribution of ion transport to restitution after injury in the gastric mucosa. For this, intact sheets of stomach from the bullfrog, Rana catesbieana, were mounted in Ussing chambers. Restitution was evaluated in the presence or absence of ion transport inhibitors amiloride, DIDS and bumetanide to block Na⁺/H⁺ exchange, Cl^-/HCO₃^- exchange and Na⁺/HCO₃^- cotransport, and Na⁺-K⁺-2Cl^- cotransport, respectively. Ion substitution experiments with Na⁺-free, Cl^--free, and HCO₃^--free solutions were also performed. Injury to the mucosa was produced with 1 M NaCl and restitution was evaluated by recovery of transepithelial resistance (TER), mannitol flux, and morphology. Amiloride, bumetanide, Cl^--free, or HCO₃^--solutions, did not affect restitution. In Na⁺-free solutions, recovery of TER and mannitol flux did not occur because surface cells did not attach to the underlying basement membrane. In contrast, all aspects of restitution were inhibited by DIDS, a compound that inhibits Na⁺-dependent HCO₃^- transport. Because HCO₃^--free solutions did not inhibit restitution, it was concluded that DIDS must block a yet undefined pathway not involved in HCO₃^- ion transport but essential for cell migration after injury and restitution in the gastric mucosa.