Metrizamide is a non-ionic water-soluble contrast medium which is isotonic with human blood and tissue fluid at a concentration of 170 mgI/ml. Retrobulbar injection of 3 ml isotonic metrizamide in the muscular conus of rabbits causes slight and inconstant cellulitis, but a similar reaction can also be found after injection of the same amount of saline. It seems probable that the introduction of fluid sufficient to cause an increase in the retrobulbar pressure can cause inflammatory changes in the orbital tissue, and that this is not always caused by the contrast medium itself. Four patients were examined by orbitography with injection of 4 ml isotonic metrizamide. There were no side effects, and the orbitograms showed contrast of good quality. Metrizamide is therefore considered very suitable for orbitography, especially in hospitals where computer-tomography is not yet available.