Sex hormones exert a substantial effect on brain function; their action is determined by the predominance of one hormone group over the remaining ones. Estrogens have indirect and direct neuroprotective effects. The indirect effects involve improved function of the vascular endothelium and increased blood flow through the brain. The direct effects (nervous cells and glia) consist in strong antioxidative properties, maintenance of Ca+2 homeostasis, blockage of activating amino acids, modification of tissue and humoral immune responses and inhibition of activity of immediate early genes. Gestagens, on the other hand, prevent neuronal death, inhibit lipid membrane peroxidation, and promote growth of nervous cells and formation of new synapses. The role of sex hormones within the brain is equally important. However, in cases of brain pathology, protective effects of gestagens seem to be much strongly expressed.