STEROIDS1-24(especially prednisolone and dexamethasone) and hypertonic solutions25,26(especially urea27-30and mannitol31-35) have been used for the medical treatment of increased intracranial pressure. Each drug has advocates and opponents. Among other controversial subjects, the phenomenon of "rebound overshoot"36-39has remained unsolved. There are some38who emphasize the importance of the presence of the secondary overshoot of pressure after the use of hypertonic solutions, and others37who deny this phenomenon. The purpose of this study is to compare the effects of the hypertonic solutions as well as steroids on cerebrospinal fluid (CSF) pressure in normal and pathological states with special reference to pressure changes and the problem of "overshoot." To begin with, it was suspected that the above mentioned drugs may have a different effect on normal vs pathological states of the brain and CSF pressure. For this reason, the study was carried