To investigate the prevalence of gastritis and H. pylori infection among young Chinese in Henan Province, a high incidence area for oesophageal cancer in China, the gastric mucosa was examined in 194 asymptomatic subjects, aged 15-26 years, in the course of an epidemiological study of precursor lesions of oesophageal cancer. Histopathological grading of gastritis and determination of H. pylori infection were performed on haematoxylineosin and Warthin-Starry stained section. An enzyme-linked immunosorbent assay was used to detect the presence of serum IgG antibodies to H. pylori. A very high prevalence of gastritis (93.8%) was found: 71 subjects (36.6%) presented with superficial gastritis (14 active), 94 (48.5%) with diffuse gastritis (92 active) and in 17 cases (8.8%) diffuse gastritis (16 active) was accompanied by focal atrophy. Silver staining detected H. pylori in 166 (85.6%) of the study participants. However, serological techniques identified H. pylori in only 109 (56.2%). H. pylori was seen in all the 119 cases showing histological signs of active gastritis, in 41 of the 63 cases (65%) without activity, and also in 50% (6/12) of histologically normal subjects. H. pylori infection was found to be associated with a 2.5-fold higher prevalence of chronic atrophic gastritis compared with non-atrophic gastritis. A family history of stomach cancer, consumption of pickled vegetables more than twice a month, and a high monthly salt consumption (> 500 g/month) also showed a positive association.(ABSTRACT TRUNCATED AT 250 WORDS)