The main focus of this section is to review the available information on ChEs (ChEs) and their inhibitors. The ChE enzymes cause damage to the cholinergic system by hydrolyzing the neurotransmitter acetylcholine (ACh). ChE inhibitors, playing an important role in the cholinergic system, are used in the treatment of Alzheimer’s disease (AD) because of their effects on maintaining ACh levels in brain regions and preventing Aβ accumulation by inhibiting ChE. In this context, it is important to develop many synthetic and natural origin ChE inhibitors for the treatment of abnormalities in the cholinergic system and disorders with neuropsychiatric symptoms. In this section, firstly, general information about ACh and its synthesis in the cholinergic system is given, then ChEs and their catalytic properties, their roles in AD, and their molecular forms are explained. In the following section, the active site of Cantis was defined. The anti-ChE activity of the developed inhibitors was discussed, and then the mechanism of their binding to the ChE active site was explained by molecular docking. In the final section, many types of ChE inhibitors are described and discussed in detail in this section, and the properties and binding mechanism of these inhibitors are summarized.