**1. Introduction**

Benign prostatic hyperplasia (BPH) is a term exclusively used for describing benign histological patterns in the European Association of Urology (EAU) and the American Urological Association (AUA) guidelines [1,2]. BPH could lead to benign prostatic enlargement (BPE) or benign prostatic obstruction (BPO) resulting in male lower urinary tract symptoms (LUTS). LUTS are grouped into three categories: storage (increased daytime frequency, nocturia, urgency, and urinary incontinence), voiding (hesitancy, slow stream, intermittent stream, straining, and terminal dribble), and post-micturition (post-micturition dribble and feeling of incomplete emptying) symptoms [3]. In addition to BPH, other causes of male LUTS include structural or functional abnormalities of the bladder and its surrounding tissues, and some non-urological conditions [4]. Lower urinary tract dysfunction (LUTD) is defined as signs observed by the physician, including simple means, to verify and quantify symptoms [3]. From a clinical perspective, BPH usually refers to LUTD caused by BPE or BPO.

We conducted a review of published literature in Pubmed, using Botulinum toxin, BPH, bladder outlet obstruction (BOO), inflammation, LUTS, and prostatitis as the key words. We reviewed the mechanisms of BPH pathogenesis and anti-inflammatory effects of BoNT-A. We tried to determine the role of botulinum toxin A (BoNT-A) in treatment of LUTS/BPH.
