Variants of intestinal metaplasia in the evolution of chronic atrophic gastritis and gastric ulcer. A follow up study. A follow up study with biopsy was initiated in 1982 to define the relations between variants of intestinal metaplasia and the evolution of chronic atrophic gastritis and gastric ulcer. All patients (58 with chronic atrophic gastritis and 66 with gastric ulcer) had intestinal metaplasia at the start of the study. In the six year period to 1988 a total of 241 biopsies were performed on the patients with chronic atrophic gastritis and 243 on the patients with gastric ulcer. Initially, 81% of the patients with chronic atrophic gastritis presented with type I intestinal metaplasia and 14% with type III intestinal metaplasia. During follow up type I was predominant, often associated with grades 2 and 3 active disease (81%) and 45% of these patients reverted to a non-intestinal metaplasia status by the third year of follow up. In contrast, type III metaplasia was more common in the absence of appreciable inflammation (78% of biopsy specimens), being persistent in five of seven patients in the third year of follow up, and was found to be associated with dysplasia in three of these patients. Similarly, the initial biopsy specimen showed type I metaplasia in most patients with gastric ulcer (82%) and type III in only 4%. Type I metaplasia was also predominant in these patients (80%), particularly in active disease (68%), gradually regressing with healing. In contrast, type III was associated with delayed ulcer healing and reactivation (75%; six of eight patients). 