Survey questionnaires can be used to characterize normal bowel habits and the prevalence of bowel dysfunction. To determine whether ethnic and sex-related differences in bowel patterns exist between Hispanics and non-Hispanics whites, we conducted a survey of a nonpatient population in El Paso, on the U.S.-Mexico border. A forced-choice, self-report questionnaire was distributed to 1014 subjects and returned by 1000. Data from the 905 Hispanic and non-Hispanic white subjects were compared. Stool frequency was analyzed by multiple linear regression, and bowel dysfunction variables were analyzed by stepwise logistic regression, in ethnic and sex groups. Data were also analyzed controlling for age, socioeconomic status, dietary factors, and use of laxatives. There was a significant sex difference in mean number of stools per week reported (P < 0.0001): Hispanic males greater than Hispanic females (8.6 vs 7.5) and non-Hispanic white males greater than non-Hispanic white females (9.3 vs 7.2). The frequency of irritable bowel syndrome-type symptoms was greater in females than in males (23.4% vs 9.6%, P < 0.001) and was less in Hispanics than non-Hispanic whites (16.9% vs 21.8%, P < 0.05), but a significant ethnic difference was not found after controlling for covariates. Additionally, females reported more alternating bowel pattern (44.0% vs 28.5%, P < 0.001) and constipation (25.5% vs 12.4%, P < 0.01) than males, and non-Hispanic white females more abdominal pain than the other subgroups (P < 0.05). Ethnic differences in dietary factors that may be relevant to bowel function were identified.(ABSTRACT TRUNCATED AT 250 WORDS)