5-Fluorouracil-induced small bowel toxicity in a patient with colorectal cancer

5-Fluorouracil-induced gastro-intestinal toxicity predominantly affects the upper and the lower gastro-intestinal tract. Although 5-fluorouracil (5-FU) can cause severe small-bowel toxicity, this has been reported only in 6 patients with colon carcinoma receiving 5-FU-based therapy. The presentation was extensive ulceration and inflammation of the small bowel with no involvement of the colon. We report another case of this toxicity, and discuss the diagnosis and mechanisms by which 5-FU can induce small-bowel toxicity.