In a Dutch working population, the apparent association between dyspeptic symptoms and Helicobacter pylori infection was found to be entirely due to subjects with an ulcer history. In general populations with a much higher prevalence of H. pylori infection and peptic ulcer disease, such as in Japan, the relationship between dyspepsia and H. pylori has yet to be clarified. A questionnaire on ulcer history and dyspeptic symptoms during the preceding 3 month period was obtained from apparently healthy Japanese employees who underwent a periodic medical examination. In addition, serum samples were analysed for anti-H. pylori IgG antibodies. A total of 196 men and 35 women, aged 23-71 years, participated in the study. Seven women (20%) and 49 men (25%) had a diagnosis of peptic ulcer disease. Among 41 subjects with verified duodenal (26) and/or gastric (17) ulcer, 95% were H. pylori positive while 32% had had frequent dyspeptic symptoms in the 3 months prior to the study (29% of the 35 men and 50% of the 6 women). Among the 147 men and 28 women without an ulcer history, the 3 month period prevalence of frequent dyspepsia was 14 and 32%, respectively. The rate of H. pylori positivity was 80% in non-ulcer dyspeptics and 68% in all other non-ulcer subjects (95% confidence intervals: 61-92 and 61-76%, respectively). Significant differences in symptoms between H. pylori positive and negative subjects could not be detected, neither in the whole population nor in the non-ulcer group. In conclusion, in this Japanese working population, no association was found between dyspeptic symptoms and H. pylori infection, irrespective of the inclusion of subjects with a peptic ulcer history.