From the Manufacturer:
Beta-sitosterol is plant sterol found in almost all plants. The American diet simply does not contain near enough of this nutrient. It's many uses include helping to maintain normal cholesterol, promotion of prostate health and helping to balance blood sugar levels.
Recent studies indicate that Beta-Sitosterol can be extremely helpful for men with symptoms of benign prostatic hyperplasia (BPH). A 1999 review of four clinical trials involving 519 men with mild to moderate BPH found that beta-sitosterol provided notible relief from urinary problems. It also increased urine flow and caused few side effects. Interestingly, benefits matched those commonly seen with prescription BPH drugs.