The development and extension of fundal gastritis and intestinal metaplasia were investigated by the endoscopic Congo red-methylene blue test in 44 healthy subjects, 106 patients with gastric ulcer, and 26 patients with gastric polyp. Follow-up chromoendoscopic examinations were made an average of 3.4 yr (range 1-10 yr) after the initial endoscopic assessment. Fundal gastritis and intestinal metaplasia developed or became more extensive with time in only 3 (6.8%) and 2 (4.5%) healthy subjects, respectively. In patients with gastric ulcer and in those with gastric polyp, fundal gastritis and intestinal metaplasia developed or extended significantly more frequently and more rapidly than in healthy subjects. Fundal gastritis and intestinal metaplasia developed or became more extensive, respectively, in 26 (24.5%) and 23 (21.7%) patients with gastric ulcer and in 10 (38.5%) and 10 (38.5%) patients with gastric polyp. Fundal gastritis and intestinal metaplasia extended with time mainly in an upward direction.