tokens: In this group of 45 patients under protection with MESNA there were 5 complete remissions and 9 partial remissions ( total 31 %). A further group of 25 patients under polychemotherapy with IF were treated by conventional prophylactic measures ( raised fluid intake and forced diuresis ). In this group there were 1 complete and 5 partial remissions ( total 24 %), but nearly all patients developed either gross haematuria and / or symptoms of bladder irritation ( cystitis and pollakisuria ). There were no appreciable differences between the MESNA series and the conventional prophylaxis series with respect to either haematological or systemic toxicity of the cytostatic treatment .