Two patients with long-standing tetraplegia after spinal cord injury developed reflex penile erection in the operation theatre. One had not received any anaesthesia, and penile erection occurred after introduction of the cystoscope into the urethra, and also autonomic dysreflexia. Intravenous salbutamol, in a dose of 10 micrograms, produced immediate and persistent penile detumescence and salbutamol-induced fall in blood pressure was of therapeutic value. In the second patient, penile erection occurred during general anaesthesia prior to cystoscopy. Immediate and persistent penile detumescence was achieved with intravenous salbutamol 20 micrograms. There was transient fall of blood pressure which responded to intravenous infusion of 0.9% sodium chloride. Salbutamol-induced fall in blood pressure is of therapeutic value in those spinal cord injury patients who develop, in addition to penile erection, autonomic dysreflexia precipitated by urethral instrumentation, or bladder distension with the irrigating fluid. Intravenous salbutamol is preferable to intra-cavernosal phenylephrine, noradrenaline, metaraminol, and epinephrine, or intravenous ephedrine which are contraindicated in patients with hypertension.