Safety and Toxicity of Saw palmetto in the Complementary and Alternative Medicine for Urological Symptoms (CAMUS) Trial
Avins AL, Lee JY, Meyers CM, Barry MJ; Complementary and Alternative Medicine for Urologic Symptoms (CAMUS) Study Group. J Urol. 2012 Oct 9. pii: S0022-5347(12)05181-6. doi: 10.1016/j.juro.2012.10.002. [Epub ahead of print]


Northern California Kaiser-Permanente Division of Research, Oakland, CA; Departments of Medicine and Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, CA. Electronic address:



Extracts of the saw palmetto berry are used by many men in the U.S. as self-treatment for lower urinary tract symptoms due to benign prostatic hyperplasia. While the most recent data from double-blind clinical trials do not support efficacy superior to that of placebo, there are few data on the toxicity of saw palmetto.


369 patients were randomized in the Complementary and Alternative Medicine for Urological Symptoms (CAMUS) trial; 357 participants are included in this modified intention-to-treat analysis. Participants were randomized to 320mg, 640mg, and 960mg daily of an ethanolic saw palmetto extract or an identical-appearing placebo, in an escalating manner at 6-month intervals, for a total of 18 months follow-up. Adverse-event assessments, vital signs, and blood and urine laboratory tests were obtained at regular intervals.


There were no statistically significant differences between groups in rates of serious or non-serious adverse events, changes in vital signs, digital prostate exam findings, or study withdrawal rates. Overall, there were no significant inter-group differences in the occurrence of laboratory-test abnormalities; differences in individual laboratory tests were uncommon and small in magnitude. No evidence of significant dose-response phenomena were identified.


The saw palmetto extract used in the CAMUS trial showed no evidence of toxicity at doses up to three times the usual clinical dose over a period of 18 months.