BACKGROUND: Hyperosmotic water-soluble contrast materials have been found to be helpful diagnostic tools in postoperative small-bowel obstruction (POSBO); however, their therapeutic value remains controversial. PATIENTS AND METHODS: A prospective, randomized clinical study was conducted to examine the use of meglumine ioxitalamate as a supplement to the standard conservative treatment of POSBO. Patients with POSBO (n = 50) suitable for a conservative approach were randomized to receive standard conservative treatment with (n = 25) or without (n = 25) the addition of 100 mL of meglumine ioxitalamate via the nasogastric tube (patients with diffuse carcinomatosis and early POSBO were excluded). Both groups were compared for resolution of obstruction, need for surgical relief of obstruction, and complications. RESULTS: Seven (14%) patients required surgery: 3 in the contrast material group and 4 in the control group (P = not significant [NS]). Resolution of symptoms was achieved in nonsurgical patients within an average of 25.7 hours in the contrast material group and 28.7 hours in the control group (P = NS). There was no mortality in this study. In 2 (4%) patients (1 in each group), strangulated bowel was found during surgery, but only the 1 (2%) patient in the contrast material group required bowel resection. No difference was found in the length of hospital stay or rate of complications. There were no complications that could be attributed to the use of the contrast material itself. CONCLUSIONS: Although water-soluble contrast material is a safe and useful diagnostic tool, it offers no advantage as a supplement to the usual conservative treatment of POSBO.