The aim of the study was to evaluate the prevalence of subjective perception of dry mouth in an adult population and to determine the prevalence of pharmacotherapy in this population. An additional aim was to assess a possible co-morbidity between symptoms of dry mouth and continuing pharmacotherapy. Four-thousand-two-hundred persons were selected at random from the national census register of the adult population of the southern part of the province of Halland, Sweden. The sample was stratified according to age and sex, and 300 men and an equal number of women aged 20, 30, 40, 50, 60, 70 and 80, were included. A newly developed questionnaire was mailed to each individual. In addition to questions about subjective perception of dry mouth, the subjects were asked to report on present diseases and continuing pharmacotherapy. Three-thousand-three-hundred and thirteen (80.5%) evaluable questionnaires were returned. The estimated prevalence of xerostomia in the population was 21.3% and 27.3% for men and women, respectively. This difference between the sexes was statistically significant. In non-medicated subjects, women tended to report a higher prevalence of xerostomia compared with men, 18.8% vs. 14.6%, and also among medicated subjects the estimated prevalence of dry mouth was higher for women than for men, 32.5% vs. 28.4%. There was a strong association between xerostomia and increasing age and also between xerostomia and continuing pharmacotherapy. The average prevalence of dry mouth among medicated and non-medicated subjects was 32.1% and 16.9%, respectively, the difference being statistically significant. There was also a strong association between xerostomia and the number of medications. In a logistic regression, the probability of reporting mouth dryness was significantly greater in older subjects and in women, and the probability increased with the number of medications taken. In conclusion, this epidemiological survey of an adult population has demonstrated that women, independent of age, do report a higher prevalence of xerostomia than men and that the symptom of dry mouth is strongly associated with age and pharmacotherapy. It is, however, not possible to discriminate between disease and pharmacotherapy as causal factors.