Giving electroacupuncture at unilateral "Biguan" and "Zusanli"points
we observed the rat subcu-taneous mast cells of "Tianshu"
"Biguan"
"Futu"
"Zusanli"and "Xiajuxu" acupoints in bilateral Sta-mach Meridian. It was found that the numbers of mast cells in all the acupoints studied were higherthan that in the non acupoint area. The numbers of mast cell in acupoints were increased under elec-troacupuncture
while that in non acupoint area was not changed. The results suggested the mast cellsplay an important role in the functions of the Meridian.