Iocarmic acid is a molecule used in seventies as a contrast media for myelography. Iocarmate meglumine (Dimer-X), a water-soluble salt of iocarmic acid was reported to be safe and best tolerated by central nervous system compared to metrizamide in a double-blind test in patients with symptoms of lumbar and sacral root involvement. In the experimental and clinical studies of Dimer-X used for ventriculography the apparent superiority of Dimer-X over Conray 60 and Angiografin as far as side effects were concerned was demonstrated, but there were no particular differences in the intensities of the ventriculograms obtained. Morphological studies of the ventricles and histological examinations of the ventricular walls 1 month after injections of Dimer-X into the ventricles of dogs showed no abnormalities. In the clinical studies, ventriculography Dimer-X, performed on patients with diseases of the central nervous system, produced ventriculograms of good diagnostic value with no side effects, such as convulsions, apart from mild headache or vomiting in 4 instances. Ventriculography with Dimer-X was carried in 15 infants with myelomeningocele and progressive hydrocephalus. However, as was shown in a number of studies iocarmate produced moderate to severe arachnoiditis from myelography in primates. Early meningitis side effects following lumbar radiculography with iocarmate meglumine were demonstrated.