AIM To investigate the effects of different concentrations of calcitonin gene related peptide (CGRP) on cultured anoxic human umbilical vein endothelial cells. METHODS An anoxia model was established by using cultured human umbilical vein endothelial cells. The endothelium membrane fluidity, 51 Cr release rate, uptake rate of trypanblue and intracellular calcium and magnesium contents were measured before and after 120 min anoxia and the effects of 1×10 -9 , 1×10 -8 and 1×10 -7 mol·L -1 CGRP on anoxic endothelial cells were studied. RESULTS The endothelium microviscosity of membrane fluidity (η) and 51 Cr release rate significantly increased and contents of endothelium magnesium decreased and uptake rate of trypanblue and contents of endothelium calcium remained unchanged after 120 min anoxia. CGRP at concentration of 1×10 -9 , 1×10 -8 and 1×10 -7 mol·L -1 was able to reduce the endothelium microviscosity of membrane fluidity (η) and 51 Cr release rate and the loss of magnesium after 120 min of anoxia while CGRP at a concentration of 1×10 -8 mol·L -1 had the best effects. CONCLUSION CGRP might lessen the damage of anoxic endothelial cells in a concentrationdependent manner, suggesting that CGRP may directly protect the endothelial cells afflicted with anoxic injury, which is related with its concentration.