Objectives: The primary objective of this project is to: determine if the daily use of saw palmetto (Serenoa repens) extract results in improvement of symptoms and objective measures of urinary obstruction relative to placebo in men with moderate-to-severe benign prostatic hyperplasia (BPH).

Secondary objectives of this project are to:

1. Determine the safety of saw palmetto extract and side effects associated with daily use over a one-year period;

2. Compare the changes in general and BPH-specific quality of life associated with use of saw palmetto extract relative to placebo;

3. Determine the effect of saw palmetto extract on biological parameters to give insight into potential mechanisms of action (should evidence of efficacy be identified);

4. Determine the effect of therapeutic expectancy on response to treatment in patients with moderate-to-severe BPH.

Research plan and methods: This study is a double-blind, placebo-controlled randomized clinical trial of the effect saw palmetto extract on symptoms, objective parameters of disease severity, and quality of life in men with moderate-to-severe benign prostatic hyperplasia.

After a single-blind placebo run-in period, 224 patients with moderate-to-severe BPH (American Urological Association Symptom Index score 8) and objective measurement of urinary obstruction, will be randomized to receive either 160mg BID of the herbal extract or an identical placebo. Patients will discontinue any other medical therapy for BPH prior to enrollment and all participants will undergo a trans-rectal ultrasound examination at baseline and closeout. Participants in the trial will be seen at 3-month intervals for a total one-year follow-up.

Outcome measurements include changes in the AUASI score (the primary outcome measurement), the peak urinary flow rate, the post-void residual urine volume, the BPH Impact Index, the Olmstead County Study Questionnaire of BPH-specific symptoms and quality of life, and the Short-Form 36 (a generic health status instrument). Numerous laboratory parameters will be measured at intervals throughout the trial and symptomatic side effects will be assessed.