To test the null hypothesis that frequent and multiple salivary exposure is not a risk factor for developing H. pylori infection, serum anti-H. pylori IgG from 179 dentists and dental students and 179 age-, sex- and socioeconomic-matched controls were assayed using an ELISA. Seroprevalence in dentists was 16% (11/70); clinical dental students 6% (3/47); and pre-clinical dental students 10% (6/62). There were no differences in H. pylori seropositivity between cases and controls. There was an increase in H. pylori seropositivity with age (chi (trend)2 9.04, p = 0.003). These data provide evidence that adults are not at high risk of developing H. pylori infection as a result of exposures to saliva from multiple sources.