The purpose of the present study was to determine the relationship between fiber intake, constipation, and clinical venous disease in the general population. The Edinburgh Vein Study was comprised of 1566 men and women aged 18-64 years who were selected at random from the age-sex registers of 12 general practices. Fiber intake, intestinal transit time, defecation frequency and the prevalence of straining at stool were all found to be significantly different between the sexes. Men who reported that they strained to start passing a motion showed a higher prevalence of mild and severe trunk varices compared to men who did not strain. After adjustment for social class, BMI and mobility at work, this group of men showed a significantly elevated risk of having severe trunk varices (OR 2.76, 95% CI 1.16, 6.58). In contrast, no consistent relationships were seen among women. Overall, within this Western general population, an association between dietary fiber, constipation and the presence or severity of varicose veins was not supported.