Alzheimer's disease (AD) is the most common form of dementia. Alzheimer's disease is unique for every individual. In the early stages, the most commonly recognised symptom is inability to acquire new memories, such as difficulty in recalling recently observed facts. As the disease advances, symptoms include confusion, irritability and aggression, mood swings, language breakdown, long-term memory loss, and the general withdrawal of the sufferer as their senses decline. Gradually, bodily functions are lost, ultimately leading to death. It was found that among three natural compounds Bulbocapnine is the best natural compound and better than commercial drugs and hence can be taken as AD chemopreventive agent and it can be effective inhibitors for AchE in AD pathway.