Side effects following myelography with positive contrast media have been reported with varying frequency and have usually been ascribed to meningeal reaction. An experimental histologic examination of the spinal cord, nerve roots and meninges after myelography with iodophendylate and methiodal was undertaken.The results of this investigation will be briefly summarized with special reference to the roentgenologic findings. Comparison will be made to complications in myelography in human subjects and precautions necessary in this procedure will be suggested. ResultsIodophendylate. Thirty-four rats weighing 250 ± 40 g were injected with 0.15 ml iodophendylate (Pantopaque) by suboccipital puncture. The amount was calculated to the proportional weight of the spinal cord in rats and men and