Chronic prostatitis can cause pain and urinary symptoms, and usually occurs without positive bacterial cultures from prostatic secretions (known as chronic abacterial prostatitis or chronic pelvic pain syndrome [CP/CPPS]). Bacterial infection can result from urinary tract instrumentation, but the cause and natural history of CP/CPPS are unknown.We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of treatments for chronic bacterial prostatitis? What are the effects of treatments for chronic abacterial prostatitis/chronic pelvic pain syndrome? We searched: Medline, Embase, The Cochrane Library, and other important databases up to August 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).We found 33 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.In this systematic review, we present information relating to the effectiveness and safety of the following interventions: 5 alpha-reductase inhibitors, allopurinol, alpha-blockers, biofeedback, local injections of antimicrobial drugs, mepartricin, non-steroidal anti-inflammatory drugs (NSAIDs), oral antimicrobial drugs, pentosan polysulfate, prostatic massage, quercetin, radical prostatectomy, sitz baths, transurethral microwave thermotherapy, and transurethral resection.