Various bioactive substances isolated from natural products play a pivotal role in the prevention and cure of neurodegenerative diseases, such as Alzheimer’s disease. Currently, there are many theories about the pathogenesis of this disease. In this review we discuss among them, the cholinergic hypotheses, the Aβ toxicity hypothesis, and the tau dysfunction hypothesis. Multiple potential targets are a focus for the development of anti-AD drugs. There is an urgent need to develop more effective therapies to treat and delay the onset of the disease and to find safe and effective drugs. In this review, the recent progress of anti-AD effects and their principal targets are updated.