Saw Palmetto

James Metz, MD
Abramson Cancer Center of the University of Pennsylvania
Last Modified: November 1, 2001

Saw palmetto is an herbal therapy whose active ingredient comes from the berries of the American dwarf palm. The plant thrives in the southeastern United States and it was originally used by the Seminole Indians as a medicinal. Saw palmetto is most commonly recommended for the treatment of benign prostatic hypertrophy (BPH), an enlarged prostate gland.

A number of clinical trials have been performed to evaluate the effectiveness of saw palmetto for control of the symptoms of BPH. A systematic review and analysis of all prospective trials including saw palmetto was reported in the Journal of the American Medical Association. Although the scientific literature is limited due to variation in study designs, short duration of follow-up, and reporting of scientific outcomes, the evidence seems to favor some benefit to saw palmetto. Compared with the common prescription medication prescribed for BPH, saw palmetto showed similar improvement in urinary symptoms and urine flow with few side effects. The exact mechanism of action is unknown, although theories abound.

Saw palmetto comes as tablets, capsules, teas and berries. Although side effects are rare, they may include high blood pressure, abdominal pain, nausea, diarrhea, decreased sex drive, impotence, urinary retention and headache. More scientific study is needed to fully evaluate the impact of saw palmetto on the prostate specific antigen (PSA) blood test. Until adequate data is available, it is prudent to discuss the utilization of this therapy with your physician particularly in regards to the PSA blood test. The PSA level should be measured by your physician before starting saw palmetto to establish a baseline value. It must be emphasized; there is no evidence that saw palmetto is effective in the treatment of prostate cancer.

It should always be remembered that any herbal treatment can interact with conventional medications. This can cause alterations of blood levels of prescribed medications and alter the effectiveness of these medications. Also, the toxicities of conventional medications may be enhanced by an herbal therapy. Always take time to discuss the utilization of unconventional medications with your health care provider before starting any therapy.