Overactive bladder is a common condition that causes sudden urges to urinate, frequent urination, night-time urination, and sometimes leakage of urine. Many people with overactive bladder improve with lifestyle changes and medicines. However, some patients do not respond to these standard treatments and continue to suffer from bothersome symptoms. This study is designed to help patients who have not improved with available medical therapy. Two treatments will be compared in this research. The first treatment uses platelet-rich plasma. Platelet-rich plasma is made from a patient's own blood and contains growth factors that may help repair the lining of the bladder and improve bladder function. The second treatment uses botulinum toxin. Botulinum toxin is a protein that can reduce unwanted bladder contractions and is already approved for use in patients with overactive bladder who did not respond to other treatments. The purpose of this study is to evaluate whether platelet-rich plasma injection into the bladder wall is safe, effective, and durable when compared with botulinum toxin injection into the bladder muscle. We believe that platelet-rich plasma may improve bladder health by encouraging tissue repair and reducing inflammation, while botulinum toxin may reduce bladder overactivity by blocking chemical signals that cause muscle contractions. This study will take place at Benha University Hospital in Egypt. About 48 adult participants with overactive bladder that has not improved after at least six months of medical therapy will be enrolled. Participants will be randomly assigned to one of two groups. One group will receive platelet-rich plasma injections into the bladder lining, and the other group will receive botulinum toxin injections into the bladder muscle. The procedures will be performed under anesthesia using a cystoscope, which is a thin instrument inserted into the bladder. Participants will be followed for one year. At several time points during follow-up, they will complete bladder symptom questionnaires, keep a voiding diary, and undergo urodynamic studies to measure bladder capacity and function. Researchers will also monitor safety by recording any side effects, such as urinary tract infections or temporary difficulty emptying the bladder. The main goal of this study is to determine whether platelet-rich plasma can reduce symptoms of overactive bladder as effectively as botulinum toxin, with fewer side effects and longer-lasting results. If successful, platelet-rich plasma could offer a new treatment option for patients who continue to struggle with overactive bladder despite standard medical therapy.