Tetrahydroberberine (THB) is an isoquinoline alkaloid originally found in Corydalis. THB exhibits antithrombotic/anticoagulant, anti-arrhythmic, neuroprotective, and gastric motility-modulating activities. In vitro, THB inhibits tissue factor pro-coagulant activity; in vivo, it inhibits arachidonic acid-induced platelet aggregation. In animal models of cardiac ischemia/reperfusion, THB decreases levels of xanthine oxidase and malondialdehyde, decreasing ventricular tachycardia and ventricular fibrillation. In neurons, THB exhibits potential benefit in animal models of Parkinson’s disease, inhibiting K(ATP) K+ channels and increasing firing of action potentials. THB also inhibits D2 dopaminergic receptors and activates 5-HT1A receptors, increasing gastric emptying in animal models and displaying potential benefit in the treatment of functional dyspepsia.