Mucosa protective drugs are thought to have an important role in the treatment of both duodenal (DU) and gastric ulcer (GU) disease by means of correcting the disturbed defensive factors. Sucralfate as well as colloidal bismuth subcitrate (CBS) form a layer on the ulcer base and in this way protect the ulcer from acid, peptic activity and bile. In duodenal ulcer sucralfate and CBS have shown a significant difference in healing rate compared with placebo. The same holds true for gastric ulcer. When compared with H2-receptor antagonists the healing rates obtained with sucralfate are rather similar. The data obtained with CBS tend to be superior. Also the scores for symptomatic improvement are indistinguishable compared to that seen with H2-receptor antagonists. Especially after CBS the relapse rates of both DU and GU appear less and delayed. Mucosa protective agents are to be considered as valid alternatives to the H2-receptor antagonists.