In the light of CSFP measurements by Lundberg's method in 46 patients the authors showed the role of hyperventilation in lowering of intracranial pressure. A considerable efficacy of dexamethasone was demonstrated as well, the use of this drug permitted to achieve stabilization of CSFP during and after the operation. The investigations showed a considerable effectiveness of such drugs as mannitol and furosemide in lowering of CSFP. Pancuronium was found to be superior to suxamethonium for administration during induction of anaesthesia because the former caused no CSFP rise. In polygraphic investigations of nocturnal sleep with parallel recording of CSFP a rise of CSFP was demonstrated during REM phase of sleep.