Within the scope of a controlled double-blind study to demonstrate the effect of conservative therapy of benign prostatic hyperplasia with Harzol, ultrasonographic examination of the prostate adenoma was carried out on 23 patients before and after therapy with the trial preparation or placebo. Within a two-month treatment with Harzol, there was a significant change in the echo structure of the prostate adenoma, and this is interpreted as a reduction in the interstitial formation of oedema.