(Ivanhoe Newswire) -- Men who attempt to treat an enlarged prostate using a common herbal remedy are probably wasting their time and money, find researchers who conducted a year-long study.

Their results show no difference in symptoms between men who took two daily doses of saw palmetto extract and those who received a placebo twice a day. Neither group demonstrated significant improvements in urinary flow, prostate size, residual volume of urine after voiding, or quality of life.

Investigators say saw palmetto is commonly recommended as an alternative to drugs approved by the U.S. Food and Drug Administration for the treatment of an enlarged prostate, known medically as benign prostatic hyperplasia. A previous study conducted in 2002 showed about 2.5 million Americans were using the herb. Usage rates may be even higher in Europe, where half of all German urologists prefer to prescribe plant-based extracts over synthetic drugs to their patients.

This study involved 225 men older than 49 who were randomly assigned to either the treatment or placebo group. All had been diagnosed with moderate-to-severe benign prostatic hyperplasia.

"In this year-long randomized trial, we found that saw palmetto was not superior to placebo for improving urinary symptoms and objective measures of benign prostatic hyperplasia," study authors say.

The study was led by researchers from the University of California, San Francisco.

SOURCE: The New England Journal of Medicine, 2006;354:557-566