Current issues of ACP Journal Club are published in Annals of Internal Medicine


Review: Saw palmetto plant extract (Serenoa repens) is effective and safe in benign prostatic hyperplasia

ACP J Club. 1999 May-June;130:61. doi:10.7326/ACPJC-1999-130-3-061

Source Citation

Wilt TJ, Ishani A, Stark G, et al. Saw palmetto extracts for treatment of benign prostatic hyperplasia: a systematic review. JAMA. 1998 Nov 11; 280:1604-9.



Is saw palmetto plant extract (Serenoa repens) as effective and safe as placebo and other pharmacologic treatments in men with benign prostatic hyperplasia (BPH)?

Data sources

Studies were identified by searching MEDLINE (1966 to 1997), EMBASE/Excerpta Medica (1974 to July 1997), Phytodok (Munich, Germany), and the Cochrane Library; scanning bibliographies of relevant articles; and contacting authors and pharmaceutical companies.

Study selection

Studies in all languages were selected if they were randomized controlled trials that compared S. repens (alone or in combination with other phytotherapeutic agents) with placebo or other pharmacologic treatments for ≥ 4 weeks in men with BPH.

Data extraction

2 reviewers extracted data on study characteristics, demographic characteristics, enrollment criteria, therapy allocation, adverse effects, outcomes, and reasons for dropouts. Discrepancies were resolved by discussion. Missing information was sought from authors or sponsors.

Main results

18 of 24 studies, involving 2939 men (mean age 65 y), met the inclusion criteria. Mean study duration was 9 weeks (range 4 to 48 wk). S. repens led to greater improvement in urinary symptom scale scores (P < 0.05), clinician-rated symptoms (P < 0.001), and self-rated symptoms (P < 0.001) than did placebo (Table). S. repens and finasteride did not differ for improvement in urinary symptom scale scores (Table). Dropout rates for S. repens were greater than those for placebo (9% vs 7%, P = 0.02) but similar to those for finasteride (9% vs 11%, P = 0.87). Erectile dysfunction rates for S. repens were less than those for finasteride (1.1% vs 4.9%, P < 0.001) but did not differ from those for placebo (1.1% vs 0.7%, P = 0.58).


Saw palmetto plant extract (Serenoa repens) is more effective than placebo and is as effective as finasteride in the short term for benign prostatic hyperplasia. S. repens leads to a lower rate of erectile dysfunction than does finasteride.

Source of funding: Department of Veterans Affairs Health Services Research and Development Service.

For correspondence: Dr. T.J. Wilt, Minneapolis Veterans Affairs Medical Center (111-0), 1 Veterans Drive, Minneapolis, MN 55417, USA. FAX 612-725-2118.

Table. Saw palmetto plant (Serenoa repens [SR]) vs control at an approximate mean follow-up of 9 weeks in benign prostatic hyperplasia*

Outcomes Comparisons (no. of studies) WMD (95% CI)
Urinary symptom scale score improvement Single SR vs placebo (1) -1.41 (-2.52 to -0.30)
IPSS score improvement Single SR vs finasteride (2) 0.37 (-0.45 to 1.19)
Combination SR vs placebo (1) -3.50 (-6.75 to -0.25)
Weighted event rates RBI (95% CI) NNT (CI)
Single SR Placebo
Self-rated improvement 89% 51% 72% (21 to 144) 3 (2 to 7)
Clinician-rated improvement 67% 39% 72% (11 to 165) 4 (2 to 22)

*IPSS = International Prostate Symptom Scale; WMD = weighted mean difference. Other abbreviations defined in Glossary; NNT and weighted event rates calculated from data supplied by author.


BPH causes morbidity through bothersome lower urinary tract symptoms and events, such as acute urine retention. In this careful systematic review by Wilt and colleagues, saw palmetto extracts were better than placebo at reducing symptoms of BPH in the short term and were equivalent to results seen with finasteride. In the 1 trial that compared S. repens (in combination) with placebo for symptom improvement on the International Prostate Symptom Scale (IPSS), a group mean difference of 3.5 points favoring phytotherapy was seen. On the IPSS, men who rate themselves as 'slightly' improved have a mean score decrease of 3 points (1), which suggests that this difference is clinically important.

Should U.S. physicians follow the lead of their European counterparts and recommend plant extracts for BPH? The answer is uncertain. However, if the goal is to reduce symptoms, α-blockers, such as doxazosin, tamsulosin, or terazosin, seem to be a better choice than finasteride (2). Head-to-head trials comparing α-blockers with phytotherapy for short-term symptom relief and side effects would be most helpful at this point. Patients may also reasonably ask whether any saw palmetto preparation that they buy locally would replicate the results seen in these trials; at present, the answer to this question is also uncertain.

Michael J. Barry, MD
Massachusetts General HospitalBoston, Massachusetts, USA


1. Barry MJ, Williford WO, Chang Y, et al. Benign prostatic hyperplasia specific health status measures in clinical research: how much change in the American Urological Association symptom index and the benign prostatic hyperplasia impact index is perceptible to patients? J Urol. 1995;154:1770-4.

2. Lepor H, Williford WO, Barry MJ, et al. The efficacy of terazosin, finasteride, or both in benign prostatic hyperplasia. Veterans Affairs Cooperative Studies Benign Prostatic Hyperplasia Study Group. N Engl J Med. 1996;335:533-9.