WASHINGTON (Reuters Health) - New animal studies suggest that a herbal preparation known to reduce prostate specific antigen (PSA) levels in men with prostate cancer may have tumor-preventing properties as well.

PSA levels are known to rise sharply in men with prostate cancer, but PSA's actual role in cancer progression remains unknown. It is not yet clear whether or not a drop in PSA directly correlates to a reduction in size or spread of prostate tumors.

PC-SPES is a mixture of eight herbs, including ginseng, saw palmetto, and chrysanthemum. Clinicians began noticing several years ago that some prostate cancer patients who took the compound had reductions in PSA levels as well as some weight gain.