Benign prostatic hyperplasia (BPH) is a common problem among aging Caucasian men that produces significant morbidity and hea1th care costs. It is likely that BPH is just as common among Chinese men. Debate exists as to whether currently available surgical and pharmacological options for BPH are appropriate for men in the watchful-waiting stage of this condition. Evidence suggests that the consumption of soy isoflavones is related to lower rates of BPH among Asian men. The advantages of soy isoflavones over conventional therapies may include better patient compliance, improved safety and lower cost. Despite the fact that soy isoflavones are safe and contain a health-conferring ingredient with a defined mechanism of action, no randomised control trial has been performed using isoflavones to treat BPH. Therefore, a randomised control trial is proposed to test the tolerability and effectiveness of soy isoflavones (Soylife) verses placebo in 182 men with defined watchful waiting BPH over a period of 12 months. In this trial, patients who fulfill the inclusion criteria, will either be given 40mg of soy isoflavones capsule (once daily) or a placebo capsule. They will be reviewed every three months with maximal urine flow rate, international prostate symptoms score and quality of life measured. Baseline tests include RFT, LFT, FBC, MSU, PSA and testosterone and to be repeated at 6th month and 12th month. The investigators hypothesize that this intervention will reduce lower urinary tract symptoms and slow the progression of the disease.

Inclusion Criteria:

• Chinese ethnicity
• Age between 45-85 years
• Diagnosed to have watchful waiting BPH (Qmax< 15 ml/sec together with a voided volume of more than 150 mls)
• Not on any concurrent alternative medications for BPH
• Mentally capable to give informed written consent and willing to comply with study requirements

Exclusion Criteria:

• Prefers to have conventional medical or surgical treatment for BPH
• Concurrent treatment for unstable chronic diseases including unstable angina, poorly controlled DM (HbA1c >7.5), less than 3 months post-MI or frequent exacerbation of COPD (more than 3x in the last year)
• Known to have prostate cancer or kidney and/or liver failure
• Urinary symptoms due to known causes other than BPH including neurogenic bladder, urinary tract infection, bladder cancer, bladder stone, urethral stricture
• Previous history of prostatic surgery
• Illiterate or having difficulty in filling in a patient diary