['We evaluated men with documented chronic prostatitis and elevated serum prostate specific antigen (PSA) to determine whether treatment with antibiotics and anti-inflammatory drugs lowers serum PSA.', 'We retrospectively reviewed the records of 95 men who presented with serum PSA greater than 4 ng./ml. and were subsequently diagnosed with chronic prostatitis with greater than 10 white blood cells per high power field in expressed prostatic excretions. Patients meeting these criteria were treated with a 4-week course of antibiotics and a nonsteroidal anti-inflammatory agent. In all patients followup PSA was determined within 2 months of treatment.', 'Mean PSA decreased 36.4% from 8.48 ng./ml. before to 5.39 after treatment (p <0.001). In 44 patients (46.3%) serum PSA decreased to below 4 ng./ml. (mean 2.48) and these patients no longer had an indication for biopsy. In the remaining 51 patients serum PSA remained elevated at greater than 4 ng./ml. and they underwent double sextant transrectal ultrasound guided biopsy. Pathological study showed prostate cancer in 13 cases (25.5%), chronic inflammation in 37 (72.5%) and only benign prostatic hypertrophy in 1 (1.05%). PSA in the 13 patients with prostate cancer decreased with treatment only 4.8% from 8.32 to 7.92 ng./ml. (p >0.05). Followup PSA at a mean of 11.4 months was determined in 19 of the 44 men who responded to treatment. Mean PSA increased only 4.5% from 2.35 to 2.46 ng./ml. (p >0.05) during this followup interval.'] Does treatment of chronic prostatitis lower serum prostate specific antigen?