Résumé : The effects of acute and chronic administra- tion of corticosteroids were studied on the fundic secre- tion of 10 Heidenhain pouch dogs. Acid, pepsin and chondroitin-4-sulfate secretion is increased during chron- ic administration. There is a latent time interval before these changes become apparent. Secretions of total and acidic glycoproteins from the visible mucus are increased during chronic but not after acute corticosteroid treat- ment. The ability of the peptic and mucous cells to synthesize pepsin, chondroItin-4-sulfate and glycoproteins is not decreased but rather increased during prolonged cortisone treatment. © 1971 S. Karger AG, Basel.