The effects of lansoprazole (30 mg/day) in 18 patients with gastric ulcers and the quality of ulcer healing were studied using endoscopy (including dye endoscopy) and endoscopic ultrasonography (EUS). The results showed an 8-week endoscopic healing rate of 94.4% and an S2-stage shift rate of 11.1%. In dye endoscopic findings of 11 S1-stage patients, S1b healing with regenerated mucosa close to S2 was seen in 63.6%. In a study of EUS findings, E0 with few relapses and high quality of healing accounted for 44.4%. When E0 rates were compared with the scarring images seen in endoscopic findings, the rates were 100% for S2, 66.7% for S1b, and 33.3% for S1a. These results indicate that a high degree of ulcer healing was achieved with lansoprazole, as good contraction of the ulcer tissue and early maturation of regenerated epithelium were observed.