Due to the increased capacity of information circuits in the modern society the central nervous system is overcrowded by huge amounts of information streaming daily to individuals particularly scientists. The problem is that nowadays is lacking the relaxation and the quality of the night dreams decreases. It leads to permanent vasoconstrictions of the brain’s vessels. So a consequence headache affects more and more people being a permanent problem in their daily life. These mechanisms underline much more serious pathophysiological changes leading to serious consequences regarding Monro Kellie Doctrine. It describes the pressure-volume relationship between Intracranial Pressure (ICP), volume of Cerebrospinal Fluid (CSF) blood, brain tissue, and Cerebral Perfusion Pressure (CPP). Brain is a closed structure composed of blood and CSF (Vascular, Parenchymal and CSF). Monro Kellie Doctrine: - Vol. of Brain + CSF + Intracranial Blood = Constant (an increase in one should cause a decrease in one or both of the remaining two). Alexander Monro (1733- 1817) a Scottish anatomist applied some of the principles of physics to the cranial cavity and hypothesized that blood circulating in the cranium was of constant volume at all times. Supported by Kellie finally known as Monro Kellie Doctrine, or Hypothesis. A brain hemorrhage followed by increase in intracranial pressure can cause a displacement to the CSF or blood. Due to loss of brain volume results in an increase in blood and CSF to maintain a constant ICP. In normal state 80% is filled by brain, 10% by CSF and 10% by blood. Due to certain trauma in the brain like if something has hit on the head a mass appears; When mass is present, initially the volume of CSF decreases to compensate. If mass enlarges, not only the volume of CSF must decrease, but also the blood volume of blood (Venous blood first). If mass continues to expand, there will be an increase in ICP, the blood volume will be reduced further resulting in brain ischemia and brain death or the contents of the brain must move out the intracranial cavity, i.e. herniation of brain tissue through the foramen magnum, an event that leads to brain stem compression and death as well. Regarding the high incidences of the diseases which are based on pathophysiologigal machanisms of Monro Kellie Doctrine, it is important to introduce the new- found physiological methods of functional investigation of the regulating systems of the nervous system which ensure the capacity of compensation. This would allow to prevent the correspondent complications and reduce the clinical expression.