Direct coronal computed tomography of the pituitary fossa, before and after enhancement with intravenous contrast medium, was performed on 25 consecutive patients with hyperprolactinaemia. The images were viewed separately by two independent observers and the pituitary height, width and contour, and the visibility of the infundibulum, optic chiasm and hypothalamus were assessed. The presence and size of any possible pituitary tumour was recorded. The administration of intravenous contrast medium made no significant difference to the pituitary measurements, the visibility of the infundibulum of hypothalamus, or the detection of possible pituitary tumours. There was an inconsistent improvement in the visibility of the optic chiasm following enhancement. The arguments against an unenhanced examination are discussed and refuted. It is proposed that routine administration of intravenous contrast medium is unnecessary when investigating moderate hyperprolactinaemia.