Generate text that best answers this question: St. John's wort
Urtica dioica for treatment of benign prostatic hyperplasia: a prospective, randomized, double-blind, placebo-controlled, crossover study.
PURPOSE: To determine the effects of therapy with Urtica dioica for symptomatic relief of lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). MATERIAL AND METHODS: A 6-month, double-blind, placebo-controlled, randomized, partial crossover, comparative trial of Urtica dioica with placebo in 620 patients was conducted. Patients were evaluated using the International Prostate Symptom Score (IPSS), the maximum urinary flow rate (Qmax), postvoid residual urine volume (PVR), Serum Prostatic- Specific Antigen (PSA), testosterone levels, and prostate size. At the end of 6-month trial, unblinding revealed that patients who initially received the placebo were switched to Urtica dioica. Both groups continued the medication up to 18 months. RESULTS: 558 patients (90%) completed the study (287/305, 91% in the Urtica dioica group, and 271/315, 86% in the placebo group). By intention- to-treat analysis, at the end of 6-month trial, 232 (81%) of 287 patients in the Urtica dioica group reported improved LUTS compared with 43 (16%) of 271 patients in the placebo group (P < 0.001). Both IPSS and Qmax showed greater improvement with drug than with placebo. The IPSS went from 19.8 down to 11.8 with Urtica dioica and from 19.2 to 17.7 with placebo (P = 0.002). Peak flow rates improved by 3.4 mL/s for placebo recipients and by 8.2 mL/s for treated patients (P < 0.05). In Urtica dioica group, PVR decreased from an initial value of 73 to 36 mL (P < 0.05). No appreciable change was seen in the placebo group. Serum PSA and testosterone levels were unchanged in both groups. A modest decrease in prostate size as measured by transrectal ultrasonography (TRUS) was seen in Urtica dioica group (from 40.1 cc initially to 36.3 cc; P < 0.001). There was no change in the prostate volume at the end of study with placebo. At 18-month follow-up, only patients who continued therapy, had a favorable treatment variables value. No side effects were identified in either group. CONCLUSION: In the present study, Urtica dioica have beneficial effects in the treatment of symptomatic BPH. Further clinical trials should be conducted to confirm these results before concluding that Urtica dioica is effective.