Abstract Alzheimer disease (AD) is neurodegenerative disease. AD is characterized by progressive deterioration in cognition, function and behavi Pathological hallmarks of AD present of amyloid plaque (AB) and neurofibrillary tangles There are 2 types of drugs for AD patients, which include cholinesterase inhibitors and NMDA receptor antagonist Both of these regulate neurotransmitter release important to memory function. These therapies provide minimal symptom relief for a short period of time and have a serious adverse reaction and drug interaction. This paper provides of the pathology hypothesis in AD new drug development might help cure, delay or prevent and the progression of AD Keywords: Alzheimer, brain, free radical