Alzheimer's disease (AD) is the most common type of dementia in aging adults, and a substantial burden to patients, caregivers, and the healthcare system. It is an increasingly significant public health issue; with the number of people living with AD projected to increase dramatically over the next few decades, making the search for treatments and tools to measure disease progression increasingly urgent. This review is based on a search of Medline, the Cochrane Database of Systemic Reviews, and citation lists of relevant publications. The subject headings and keywords used were Alzheimer's disease, dementia, primary neuronal degeneration and senile plagues. Only the articles written in English were included. The diagnosis is still primarily made based on history and physical and neurologic examinations. Approved treatments are few and of limited efficacy, serving mostly to slow or delay progression and not to cure the disease, despite significant research by pharmaceutical industries. Cholinesterase inhibitors offer some help in treating cognitive and global functioning, as well as behavioral abnormalities in patients with mild-, moderate-, or severe-stage disease. The N-methyl-d-aspartate (NMDA) antagonist, memantine, is similarly effective alone or in combination with cholinesterase inhibitors in moderate to severe stages of the disease. Recent insights into the pathophysiology of AD have led to promising investigational therapies, including the development of γ- and β-secretase inhibitors as well as active and passive immunization against the amyloid β-protein.