The data of the 23 patients who were diagnosed with refractory IC/BPS and received intravesical Btx-A between January 2015 and December 2019 were retrospectively reviewed in this single-center study. The study group was named “Group 1” and evaluated in two groups as follows: Group 1A (pretreatment scores) and Group 1B (posttreatment scores). Subsequently, 23 age-matched healthy sexually active women without any urinary disease were determined as the control group(Group 2). This group was created by patients who received routine gynecological examinations in the outpatient clinic. As per our protocol, 23 patients who failed to respond to first-line treatments, such as conservative therapies, and second-line treatments, including oral analgesic drugs and intravesical injections of chondroitin sulfate, heparin, and hyaluronic acid, were included in the study group. The surgical procedure was performed by a single surgeon. Here, 100 units of Btx-A were diluted to 20 cc 0.9% saline, and 1 cc was then applied submucosally on 20 different points of the bladder wall using a 25-gauge needle (5 U/1 ml per site). A 14 F urethral Foley catheter was placed after the injection. On the second day after the injection, the catheter was removed, and all patients were discharged. At this point, patients were warned of the need for clean intermittent catheterization if deemed necessary. In the third week after the surgery, uroflowmetry was undertaken and the postvoid residual volume was measured to exclude urinary retention. Next, all patients were asked to fill out validated versions of the FSFI and ICSI (range of 0 to 20) as well as the ICPI (range of 0 to 16), visual analog scale (VAS) for pain assessment, and three-day bladder diary (BD) which were used to assess pre- and post-operative functional bladder capacity and daytime and night urinary frequency. Specifically, the FSFI questionnaire consists of 19 questions that investigate the following six domains: desire, arousal, lubrication, orgasm, pain, and satisfaction. Finally, the mean scores of FSFI, ICSI, ICPI, VAS, and BD data of the study and control groups were compared at baseline and three months after the treatment. Here, the primary endpoint was the assessment of improvement in SD, while the secondary endpoints were the changes in urinary symptoms and pain after the Btx-A injection.