<p num="78">FIELD: medicine.</p> <p num="79">SUBSTANCE: invention refers to medicine, namely to urology, and can be used to determine an algorithm for treating painful bladder syndrome (PBS) in females. Scores of the PUF, past history and cystoscopic findings are determined in points. Additionally, the Kell, O'Leary and BPIC questionnaires are assessed in points'; the presence of Hunner's involvement in cystoscopy, diffuse bleeding of the mucous membrane, diffuse submucous haemorrhages, single petechial haemorrhages and the bladder filling volume, wherein the bladder wall lesions are detected. Patient is also found to have a previous history of hysterectomy. That is followed by calculating discriminant values of classification functions of therapeutic lines S1-S3 according to the declared formulas. If S1 is simultaneously greater than S2 and S3, conservative treatment is indicated. If S2 value is simultaneously greater than S1 and S3, hydrodistention of urinary bladder is shown. If S3 is simultaneously gre