['Constipation is widely believed to cause hemorrhoids. However, recent evidence questions the importance of constipation in the development of this common disorder. In the present study, the association of hemorrhoids with constipation and other potential risk factors was examined.', 'The analysis consisted of 325 consecutive patients who underwent proctoscopy at the Milwaukee VA Medical Center during 1989. Each participant was questioned regarding hemorrhoid symptoms, bowel habits, and associated medical conditions. At the time of proctoscopy, the presence or absence of hemorrhoids was recorded.', 'Hemorrhoids were identified in 168 subjects; the remaining 157 served as controls. No significant association was observed between constipation and hemorrhoids. Increasing age, cirrhosis, and varicose veins likewise were not associated with hemorrhoids. In contrast, the subjective complaint of diarrhea [odds ratio 2.1; 95% confidence limits (CL) 1.2-3.7] and obesity (odds ratio 1.7; 95% CL 1.1-2.7) were significantly associated with the presence of hemorrhoids.'] Is constipation a risk factor for hemorrhoids : a case-control study of potential etiological agents?