Ten patients with closed head trauma and elevated intracranial pressure (ICP) ranging from 40-127 mm Hg were treated with intravenous dimethyl sulphoxide (DMSO) every 6 h for 1-10 days. Four patients received DMSO and intermittent oxygen. All patients showed a reduction of ICP after 24 h and 7 had normal ICP after 6 days of treatment. Two patients died of their injuries. Neurological assessment at the time of discharge showed 2 patients with severe neurological deficits and 6 patients with mild to no deficit. After a 3 month follow-up, 1 patient remained severely impaired and 7 patients showed mild to no deficit. It appears that intravenous DMSO can rapidly reduce elevated ICP in severe closed-head injury and that it improves neurological outcome.