A clinical study of intravesical prostaglandin E2 (PGE2) and F2 alpha (PGF2 alpha) in the treatment of 13 female patients with difficulties in emptying their bladder is reported. Urodynamic investigations were performed before and after instillation of the drug. Although 3 patients had some reduction in residual urine volume, the remainder showed no obvious change and no patient experienced subjective improvement. In 6 patients, biopsies of the vesical mucosa were taken before and after instillation in order to measure the uptake of prostaglandin by the mucosa, but no conclusions could be drawn from these measurements. Although prostaglandins are known to have contractile effects on the detrusor muscle, the results of this study suggest that intravesical PGE2 and PGF2 alpha have no therapeutic value in the treatment of voiding dysfunction and residual urine.