Phytotherapeutic agents are often prescribed in Europe for the treatment of benign prostatic hyperplasia with lower urinary tract symptoms and are commonly used in the United States in over-the-counter preparations. Saw palmetto berry is the most popular of these agents, and in vitro some studies suggest that liposterolic extract of the plant has antiandrogenic effects that inhibit the type 1 and type 2 isoenzymes of 5alpha-reductase; however there are no clinical studies that show any decrease in serum dihydrotestosterone or prostate-specific antigen. Its efficacy in the treatment of lower urinary tract symptoms has not been conclusively proven. Clinical efficacy was suggested by a meta-analysis of Permixon, a formulation of saw palmetto, but the meta-analysis was done on suboptimal studies. One trial supports the equivalency of Permixon to finasteride in treating moderate to severe symptoms of benign prostatic hyperplasia, with less decrease in sexual function. However, without a control/placebo arm, the actual efficacy of the agents cannot be determined. Other than occasional gastrointestinal upset, no other side effects have been reported.