The present study was carried out to assess comparatively the effectiveness and tolerance of norfloxacin, enoxacin and ofloxacin in the treatment and prophylaxis of infections of the low urinary tract in non-hospitalised patients. Thirty patients presenting positive uroculture on clinical evidence of ongoing infection were treated. Doses were 400 mg b.i.d. for norfloxacin, and 300 mg b.i.d. for ofloxacin and enoxacin; duration of treatment was 7 days in treatment. The pathogen was eradicated in 94% of cases at the control carried out after 5 days from the end of treatment; in the follow-up at 20 days, recurrences or reinfections were observed in 30% of the cases, almost all of them consisting of complicated infections. Slight side-effects were observed in 8 patients. No significant differences in effectiveness or tolerance were reported between the 3 quinolones under study which are therefore considered reliable overall for urological treatment. The absence of greater side-effects is related to the restriction of indications and the brevity of the therapeutic cycles.