Lavomax--a synthetic fluorenon compound and a classic oral low-molecular interferon inductor--was for the first time used in combined treatment of chronic recurrent cystitis. We compared clinico-immunological indices in the treatment of exacerbations of chronic cystitis in females given lavomax and treated without it. The course of treatment consisted of 10 tablets 0.125 g each, a prophylactic course--1 tablet a week for 6 weeks. A total of 60 females aged 19-80 years entered the trial. In women given lavomax it elevated leukocyte production of alpha and gamma interferon: on treatment day 17 interferon alpha rose to 31.25 pg/ml, gamma--to 27.29 pg/ml (double baseline level). Nine weeks since the start of the treatment the above indices lowered but stayed above normal values (25.84 and 24.4 pg/ml, 23.05 and 16.39 pg/ml, respectively). As an adjuvant, lavomax promoted faster elimination of cystitis symptoms: complaints disappeared in 50% patients while in the control group only in 17%). Eradication of the bacteria was achieved in 66.7% patients. In the controls it was 2 times less. Adjuvant use of lavomax in therapy of chronic cystitis reduced frequency of cystitis recurrences.