Acetylcholinesterase (AChE) is an enzyme that hydrolyzes acetylcholine to choline and acetate. Inthe previous reports the level of acetylcholine (ACh) was decreased in the brain of Alzheimerpatients, which has led us to focus on the research to develop a treatment inhibiting AChE. Thuswe have discussed here the effects of herbal extracts (HAN and Ginkgo) with vitamin B6 on AChEactivities in vitro and in vivo. As concentrations of herbal extracts and vitamin B6 increased, thevalue of reaction rate of AChE was decreased for the substrate acetylthiocholine (ATCh). Whenthe herbal extracts and vitamin B6 were mixed, the value of reaction rate of AChE was alsodecreased in vitro state. And they act as reversible noncompetitive type inhibitors, as shown inLineweaver-Burk plot. For an in vivo study we administrated orally the herbal extracts andvitamin B6 to rats for 10 consecutive days. The activity of AChE in brain tissues of rats wasdecreased. As a result, the AChE activity was inhibited by the herbal extracts and vitamin B6, andthey could be good drug candidates for curing Alzheimers disease.