Alzheimer's is a chronic neurodegenerative disease and the most common form of senile dementia. The greatest known risk factor of the disease is aging, so most patients with the disease are 65 years of age or older. However, it is not considered a normal part of aging, but the result of complex interactions among many factors including age, genetics, environment, lifestyle, and coexisting medical conditions. Alzheimer's disease is characterized by a progressive decline in cognitive function, which usually begins with problems with short-term memory. The disease occurs in two forms, hereditary and sporadic. Two characteristic pathological changes in the brain that occur in both forms of disease are the accumulation of amyloid β peptide in extracellular senile plaques and the accumulation of abnormal hyperphosphorylated tau protein in the intracellular neurofibrillary tangles. The neurodegenerative process of the disease is characterized by a synaptic damage which is accompanied by the loss of neurons in the cerebral cortex and certain subcortical regions of the brain. Aggregated oligomeric forms of Aβ have toxic effects to the cellular and synaptic function, causing loss of neurons and decline in cognitive function. There is no treatment that stops or reverses the progression of the disease, although some may temporarily improve the symptoms. Approved therapy includes three inhibitors of acetylcholinesterase (donepezil, galantamine and rivastigmine) and one NMDA receptor antagonist (memantin). During the development of the disease cholinergic neurons are damaged, and the inhibition of the enzyme disintegrating acetylcholine aims to increase its concentration in the brain. Likewise, during the disease, excessive stimulation of NMDA receptor by glutamate causes excitotoxicity (nerve cells are damaged by excessive stimulation by neurotransmitters), therefore NMDA receptor antagonist is used to block this effect. These medications temporarily reduce memory and thinking problems, but their clinical effect is modest. Over the past decade, the focus of discovery of new therapies is on medicines that change the course of the disease. The aim of such drugs is to slow down the progression of the neurodegenerative process by inhibiting critical events in the pathophysiology of the disease, including the deposition of extracellular senile plaques and intracellular neurofibrillary tangles. However, after decades of research, Alzheimer's disease is still incurable and is considered to be one of the major human health challenges.