The patients affected with multiple sclerosis (MS) often complain of constipation. This symptom is little tolerated by the patient; its etiology is still unknown. MS patients often have their movements impaired by disease progress, so that they have to sit down for a long time, or else they exhibit severe problems walking or moving. MS patients also present low intraabdominal pressure during voluntary contraction of abdominal wall muscles. In these patients, the authors suggest to study intestinal transit time by means of radiopaque markers. To this purpose, the radiological follow-up contributes to the setting of colorectal MS dysfunctions by daily controls of the progress of per os radiopaque markers, focusing on colonic transit time and temporary deposit areas. The results show high incidence of anorectal constipation. Thus, the examination can be considered a useful tool in the study of MS dysfunctions and an effective alternative to anorectal manometry.