Willowherb (Epilobium parviflorum Schreb) belongs to the Onagraceae family and it is typically found in Poland. Medicinal part of the plant is Epilobii herba which contains terpenes (ursolic acid), phytosterols, tannin, flavonoids (quercitin), phenolic acids. Products made from willowherb are traditionally used for treatment of benign prostate enlargement. They reduce problems with lower part of urinary system and urinating. Willowherb can be used only after other serious diseases are excluded.