Alzheimer__ampersandsign#39;s was first discovered by Alois Alzheimer in 1906. It is a progressive neurologic disease of the brain leading to the irreversible loss of neurons and the loss of intellectual abilities, including memory and reasoning, which becomes severe enough to impede social or occupational functioning. There is no current cure for Alzheimer__ampersandsign#39;s, although there are ways of slowing down its advances and helping patients with some of the symptoms. Lifestyle factors that help ward off or slow down Alzheimer__ampersandsign#39;s include yard work, gardening, dancing, riding an exercise, and any type of aerobic exercise. Alzheimer__ampersandsign#39;s disease is the most common type of dementia, in fact it accounts for almost fifty percent of all dementia cases. Dementia is a term given to a few disorders that affect the brain causing problems with memory, speech, and perception. Dementia causes the victim to forget everyday occurrences, and the person may have problems in understanding concepts or words, and may have horrible mood swings. This review describes both Alzheimer?s and Dementia in details and also enlists the difference between them.