AbstractPatients suffering from the interval form of carbon monoxide poisoning, believed to recover only with difficulty, were successfully treated by application of oxygen at high pressure (OHP) treatment. Nine out of 10 patients responded well to the treatment and recovered to the level of normal daily life. The occurrence of this interval sequela of carbon monoxide poisoning is difficult to predict during the lucid interval. In two of our cases the findings of serial EEG examinations became worse during the lucid interval followed by the occurrence of clinical symptoms. In this article, first we show the results of the clinical course of 10 patients with OHP treatment, then report the method of prediction of the interval from by serial EEG examinations.