Ivermectin selectively binds to the glutamate-gated chloride ion-channel of invertebrate neuromuscular cells, which leads to the permeability of the cell membrane to chloride ions. Increased (also allows gamma-aminobutyric acid (GABA) mediated chloride channel opening), neuromuscular cells are thus over-polarized, interfere with nerve conduction, and parasitic parasites die. While mammalian neuromuscular cells do not have glutamate chloride channels, macrocyclic lactones have low affinity for mammalian chloride channels, and ivermectin cannot pass the blood-brain barrier of mammals, so it is safe. Very high. Due to the principle of action of ivermectin, it does not directly destroy the worm and cause death, so it does not produce drug resistance.