UFT, a compound containing uracil and tegafur (a prodrug of 5-fluorouracil) in a 4:1 molar ratio, has been used in Japan for the treatment of and as adjuvant chemotherapy for bladder cancer. In phase II studies, 300 to 600 mg/day of UFT given orally for more than 4 weeks produced a 32% overall response rate, including a complete response rate of 19.0%. Toxicity was in general mild and reversible. Gastrointestinal toxicity affected 56% of patients receiving 600 mg/day and 24% of patients receiving 300 mg/day of UFT. A randomized, prospective trial was performed to determine whether long-term treatment with oral UFT (300 to 400 mg/day for 2 years) as adjuvant chemotherapy could prevent intravesical recurrence of superficial bladder cancer. Long-term UFT administration after transurethral resection, in fact, effectively prevented the recurrence of superficial bladder cancer, with acceptably low toxicity. These data suggest that UFT as a single agent is effective against bladder cancer, with mild toxicity when used properly.