Two-hour gastric acid and intrinsic factor (IF) secretory capacity determinations after betazole hydrochloride stimulation were performed on 21 patients with multiple myeloma, 10 each with lymphoproliferative disorders, rheumatoid arthritis, extragastric cancer, and 40 controls, all less than 65 years old. One patient with multiple myeloma had pernicious anemia (PA); four patients with multiple myeloma had close relatives with PA, gastric carcinoma, or thyroid disease. Two other elderly patients had myeloma and atrophic gastritis. Two patients with lymphoproliferative disorders had severely impaired gastric secretion. Parietal cell, IF, and thyroid autoantibodies were not detected in serum from any of the patients.