Abstract: The principal role of acetylcholinesterase (AChE)is the termination of nerve impulse transmission at the cholinergic synapses by rapid hydrolysis of acetylcholine (ACh). Inhibition of AChE serves as a strategy for the treatment of Alzheimer's Disease (AD). Several acetylcholinesterase inhibitors (AChEIs) are used for the symptomatic treatment of AD A potential source of AChE inhibitors is certainly provided by the abundance of plants in nature. The aim of this article is study the effect of some plants and pesticides on acetylcholinesterase. Several plants considered as a source of acetylcholinesterase inhibitors and pesticides special organophosphorus.