Fraxinellone, a natural product isolated and purified from the root barks of Dictamnus dasycarpus Turcz. with neuroprotective, vasorelaxing, insecticidal, and antimicrobial activities, is a selective blocker of voltage-dependent Ca2+ channel, while dictamine relaxed the rat aorta by suppressing the Ca2+ influx through both voltage-dependent and receptor-operated Ca2+ channels, and can dramatically induce apoptosis of activated peripheral CD4(+) T cells in vivo, consequently resulting in less CD4(+) T-cell activation and infiltration to the liver.