Mesnal 400 mg Injection (Mesna) is a prescription uroprotective medicine used alongside chemotherapy to prevent hemorrhagic cystitis (bladder bleeding and irritation) caused by certain cancer drugs, especially ifosfamide and high-dose cyclophosphamide. Mesna works by chemically binding and neutralizing harmful metabolites (such as acrolein) produced during chemotherapy breakdown in the urinary tract, thereby protecting the bladder lining. This medicine is administered intravenously by trained medical professionals and is an important supportive therapy in many oncology treatment plans. A valid doctor’s prescription and medical supervision are required for safe and effective use.