Willowherb Epilobiumparviflorum Schreb. belongs to the Oenotheraceae willowherb family, it is commonly found in Poland. The herb of willowherb Epilobii herba is the medicinal raw material, containing terpenes (ursolic acid), phytosterols, tannins, flavonoids (quercitrin, quercetin), phenolic acids. Willowherb products from the herb are traditionally used in benign prostatic hypertrophy in order to alleviate the symptoms from the lower urinary system, such as difficulty urinating or frequent need to urinate. The herb of willowherb should be used after a physician would exclude severe conditions.