OUTLINE: This is a randomized, double blind, multicenter study. Patients are stratified according to disease status (newly diagnosed vs recurrent), clinical stage (Ta vs T1), grade (G1 vs G2), and focus (multifocal vs unifocal). Patients receive either oral eflornithine or placebo once daily. Treatment continues for 1 year in the absence of disease progression or unacceptable toxicity. Patients are followed every 3 months during the first 2 years, every 6 months for the third year, and then annually for the fourth year.