The healing rate of duodenal ulcers may be accelerated by secretory inhibitors such as histamine H 2-receptor antagonists and pirenzepine, by antacids, by protective drugs such as sucralfate and colloidal bismuth, and by antidepressant drugs such as trimipramine. The effect of these drugs on the rate of healing is comparable; they differ with respect to practicability of treatment, incidence and types of side effects, and suitability for long-term administration. Currently, the most versatile and most thoroughly investigated drugs are the histamine H 2-receptor antagonists.