(+)-Nootkatone is sesquiterpene ketone originally isolated from grapefruit juice and peel oil with diverse biological activity. It is lethal against ticks, fleas, and mosquitoes with LC50 values of 0.0029, 0.0061, and 0.0046% w/v, respectively. Pretreatment of wood with (+)-nootkatone reduces tunnel lengths, feeding, and survival rates in C. formosanus termites. (+)-Nootkatone (10-100 µM) dose-dependently activates AMPKα1 and AMPKα2 in C2C12 mouse myoblast lysate containing a substrate peptide. It dose-dependently inhibits platelet aggregation induced by collagen, thrombin , and arachidonic acid when used at concentrations ranging from 10 to 100 μM with almost complete inhibition at the highest concentration. In vivo, (+)-nootkatone (3-30 mg/kg, p.o.) dose-dependently increases the length of tail bleeding time in mice. (+)-Nootkatone (0.1-0.3%, p.o.) dose-dependently reduces body weight and plasma glucose levels in mice fed a high-fat and high-sucrose diet.