Comparative study was performed of action of a group of 15 isoquinoline homoproaporphine and homoaporphine alkaloids, 10 tropolone colchicine alkaloids and their lumoderivatives that were isolated from corms of a representative of the lily family, the showy autumn crocus Colchicum speciosum Stev. on activity of mammalian erythrocyte acetylcholinesterase and serum butyrylcholinesterase. The studied compounds have turned out to be moderate-potency reversible inhibitors of the studied cholinesterases and to show to a certain degree some specificity of action towards different enzymes both quantitatively, by the ratio of total inhibitor constant values, and qualitatively, by the type of mechanism of the enzymatic activity inhibition. The overwhelming majority of the studied alkaloids revealed certain specificity towards butyrylcholinesterase. An exception was colchamine.