Geissoschizine methyl ether is a potent serotonin ₁A receptor agonist and candidate for amelioration of aggressiveness and sociality by yokukansan. Geissoschizine methyl ether has vasorelaxant effect, which is composed of two different mechanisms: endothelial dependency with nitric oxide and endothelial independency with voltage-dependent Ca(2+)-channel blocking.Geissoschizine methyl ether has third-generation antipsychotic-like actions at the dopamine and serotonin receptors. Geissoschizine methyl ether is a strong acetylcholinesterase (AChE) inhibitor, it inhibited 50% of AChE activity at concentrations of 3.7 ± 0.3 ug/mL. Geissoschizine methyl ether protects neurons from oxidative toxicity by shifting energy metabolism from mitochondrial respiration to glycolysis.