A total of 3,289 sections of 120 gastrectomy specimens from Chile were reviewed. Intramucosal cysts were found in 61.7% of the specimens, ciliated metaplastic cells in 33.3%, large vacuolated cells in 20.8% and extensive intestinal metaplasia in 51.7%. The frequency of these non-neoplastic changes was significantly higher in specimens with early adenocarcinoma of intestinal type than in those with early adenocarcinoma of diffuse type or having a peptic ulcer. Similar results have been recorded in other inhabitants of the Pacific basin, but not inhabitants of the Atlantic basin. Interestingly, the gastric cancer incidence in the various populations studied in the Pacific basin is much higher than in those studied in the Atlantic basin. Environmental factors acting in Chile appear to have induced those non-neoplastic changes in the gastric mucosa. The question arises as to whether environmental factors (promoters?) acting in Chile (as well as in Japan, in Hawaii and in New Zealand) have favored the necessary non-neoplastic mucosal conditions required for the subsequent development of gastric adenocarcinoma (in particular of intestinal type.)