Overactive blader (OAB) is a urological condition defined by a set of symptoms: "urgency, with or without urge incontinence, usually with frequency and nocturia." The International Continence Society(ICS) is responsible for this definition. There exists, however, some controversy over the use of this term because these symptoms taken in isolation may overlap with those of other bladder conditions, including interstitial cystitis, or rarely even bladder tumours.