Cyclovirobuxine D (CVB-D) is an active compound extracted from Buxus microphylla, which has been used of cardiac insufficiency and arrhythmias in China. The antiarrhythmic and proarrhythmic potential of this drug might be concerned with prolongation of action potential duration and QT interval. Human-ether-a-go-go-related gene (HERG) has an important role in the repolarization of the cardiac action potential. CVB-D inhibits HERG encoded potassium channels and this action might be a molecular mechanism for the previously reported APD prolongation and QT interval prolongation with this drug. Currently pharmacological studies on CVB-D have been conducted extensively for treatment of cancers. However, whether and how CVB-D affects other cellular processes and the tumorigenesis pathway of cancer cells is still largely unknown.