We encountered two chemotherapy cases related to anticancer drug-induced colitis. Case 1 was a 35-yo-female with a recurrence of ovarian cancer. She was treated with intraarterial infusion consisting of continuous 5-fluorouracil (250 mg/day 5 days/week x 4) following low-dose consecutive cisplatin (20 mg/day 5 days/ week x 1). The catheter was inserted into the abdominal aorta about 2 cm above the carina of the common iliac arteries. Six weeks after the start of chemotherapy, severe abdominal pain and melena occurred. Case 2 was a 68-yo-female with an endometrial cancer recurrence. The same intraarterial chemotherapy used in case 1 was was initiated. Four weeks after the start of chemotherapy, before intraarterial infusion of CDDP, she suffered from constipation and than diarrhea, abdominal pain and melena. Both cases were diagnosed as anticancer drug-induced colitis with the pathological findings from colon biopsy and the clinical course, and improved in about 1 month with the discontinuation of intraarterial infusion, fasting and TPN. Intraarterial infusion of only CDDP caused both patients no intestinal symptoms, so it is supposed that intraarterial infusion of 5-fluorouracil induced the colitis. Anticancer drug-induced colitis should be taken into consideration as a rare but possible course of chemotherapy-related complication with intraarterial infusion of 5-fluorouracil.