Thirteen patients with peptic ulcer were treated with fresh cabbage juice, which, experiments have indicated, contains an antipeptic ulcer factor. This factor (vitamin U) prevents the development of histamin-induced peptic ulcers in guinea pigs. The average crater healing time for seven of these patients who had duodenal ulcer was only 10.4 days, while the average time as reported in the literature, in 62 patients treated by standard therapy, was 37 days. The average crater healing time for six patients with gastric ulcer treated with cabbage juice was only 7.3 days, compared with 42 days, as reported in the literature, for six patients treated by standard therapy. The rapid healing of peptic ulcers observed radiologically and gastroscopically in 13 patients treated with fresh cabbage juice indicates that the anti-peptic ulcer dietary factor may play an important role in the genesis of peptic ulcer in man.