The relationship between the inhibition of intragastric acidity and healing has been determined for both duodenal and gastric ulcers, with a stronger correlation being evident in duodenal ulcer. Omeprazole is clearly more effective than H-2-receptor antagonists in healing duodenal ulcers and in the resolution of attendant symptoms. As the recommended treatment periods are shorter with omeprazole (e.g. 2-4 weeks) than with H-2-receptor antagonists (4-8 weeks), omeprazole has also been shown to be more cost-effective. Long-term management strategies for peptic ulcer are evolving rapidly in the light of evidence that Helicobacter pylori eradication reduces or eliminates ulcer relapse. Regimens, such as omeprazole in combination with amoxycillin or clarithromycin, that both eradicate H pylori and heal ulcers rapidly are appealing because they are simple, well tolerated, convenient and efficient in both healing ulcers and preventing relapse. This comprehensive approach appears to be evolving as the dominant strategy for the future treatment of peptic ulcer diseases. Gastric ulcer disease is also treated more effectively with omeprazole than with Hz-receptor antagonists, both in terms of speed and reliability of healing, and in terms of symptom resolution. At 4 weeks, symptom resolution has been specifically examined in six comparative trials; in three of these, omeprazole was superior to the H-2-receptor antagonist, and in the other three was at least as good as the H-2-receptor antagonist. Omeprazole, 40 mg once daily, effectively heals non-steroidal anti-inflammatory drug (NSAID)-induced ulcers in about 90% of cases, even if NSAID therapy is continued, and is probably the treatment of choice for patients with ulcers requiring continued NSAID therapy. It has yet to be determined whether inhibition of gastric acid secretion will prevent the formation of NSAID-induced gastric ulcers.