Objective: To observe the effects of essential garlic oil (EGO) on vascular cell adhesive molecule 1 (VCAM 1) expression of endothelial cells and monocyte endothelial cell adhesion rate induced by interleukin 1 α (IL 1 α). Methods: Human umbilical vein endothelial cells (HUVEC) were isolated by trypsin digestion method and co cultured with IL 1 α or EGO+IL 1 α in the absence or presence of U937 monocyte. Monocyte endothelial cell adhesion rate was examined with reverted microscope. VCAM 1 expression of endothelial cells was measured by ACAS 570 confocal microscope, and the data were presented as mean fluorescent intensity. Results: EGO significantly inhibited IL 1 α induced endothelial expression of VCAM 1, and thus markedly decreased monocyte endothelial cell adhesion rate. Conclusion: EGO has the effect on antagonizing adhesion of monocyte and vascular endothelial cell, which might be due to its inhibition on adhesive molecular expression on the surface of endothelial cells. Objective: To observe the effects of essential garlic oil (EGO) on vascular cell adhesive molecule 1 (VCAM 1) expression of endothelial cells and monocyte endothelial cell adhesion rate induced by interleukin 1 α (IL 1 α). Methods: Human umbilical vein endothelial cells (HUVEC) were isolated by trypsin digestion method and co cultured with IL 1α or EGO + IL 1α in the absence or presence of U937 monocyte. VCAM 1 expression of endothelial cells was measured by ACAS 570 confocal microscope, and the data were presented as the mean fluorescent intensity. Results: EGO significantly inhibited IL 1α induced endothelial expression of VCAM 1, and thus markedly decreased monocyte endothelial cell adhesion rate. adhesion of monocyte and vascular endothelial cells, which might be due to its inhibition on adhesive molecular expression on the surface of endothelial cells.