Albino rabbits with experimental brain edema produced by a cryogenic lesion or by a cryogenic lesion combined with a metabolic blocker. 6-aminonicotinamide. were given 1 g of a 10% solution of dimethyl sulfoxide (DMSO) per kg by intravenous bolus. Simultaneous recording of intracranial pressure (ICP). systemic arterial pressure (SAP), and central venous pressure and electroencephalography were performed while the animals were mechanically ventilated at a constant PaCO2 (PaCO2 38 to 42 torr). One hour after the administration of DMSO. the rabbits were killed by air embolus, and the brain was removed promptly for the determination of wet and dry weights and electrolyte content. The ICP at 15, 30, and 60 minutes after DMSO was lower in both groups; ICP was significantly lower at 30 minutes (P < 0.5) in the cold lesion group and at 15 minutes in the combined group (P < 0.05). There was no significant change in SAP after DMSO in either group. There was a significant reduction of brain water content after DMSO in the combined lesion group (P < 0.005 for the left hemisphere and P < 0.025 for the right); there was no significant reduction of water content in the group with a cold lesion only.