Yakuchinone B is an Acyl-CoA: cholesterol O-acyltransferase ( ACAT ) inhibitor with hypocholesterolemic activity, which is found in the seeds of Zingiberaceae. Yakuchinone B inhibits rat hepatic ACAT with an IC 50 value of 20.6 μM. Yakuchinone B is promising for research of hypercholesterolemia and atherosclerosis.