The efficacy and tolerance of a high-dose treatment with trospium chloride (20 mg twice daily) were investigated in pilot studies carried out in three trial centres and involving a total of 29 patients suffering from reflex bladder due to transverse lesions of the spinal cord with paraplegia. In all three centres the trial procedure was the same. Urodynamic measurements (maximum bladder capacity, bladder compliance, maximum detrusor pressure during micturition, urinary flow and residual urine) were taken both before and after treatment with trospium chloride for a period of at least 2 weeks. In almost all patients there was a clear rise in maximum bladder capacity, a marked decrease in maximum detrusor pressure and an increase in bladder compliance. As a result the frequency of micturitions was lowered. In the majority of patients, urinary incontinence caused by detrusor hyperreflexia was brought under control through depression of detrusor activity, and urinary continence was achieved. If necessary, intermittent catheterization was continued to empty the bladder. Tolerance of the test preparation was good, and side-effects were rare and mild.