The administration of Solco Urovac polymicrobial vaccine to 26 patients with recurrent episodes of urinary tract infection significantly reduced the number of episodes, in one third of the persons even prevented them for a period of one year. In case of persistent bacteriuria, accompanying, for example, nephrolithiasis, the vaccine had no effect. A better effect can be achieved in cases of uncomplicated infections of the lower urinary tract than in infections associated with structural abnormalities of the kidneys and urinary tract. In some patients, the administration of the vaccine is accompanied by mild side effects which, but only exceptionally, can lead to the discontinuation of the therapy.