Objective:To evaluate effect of fresh aloe treating phlebitis and find a way to cure phlebitis. Methods:Thirty healthy large-eared New Zealand rabbits were chozed. Two edged-veins in both ears were set intravenous indwelling needle mimicing real clinic transfusion. The indwelling needles were extracted when phlebitis occurred 5 days after needles setting. Then they were randomly divided into model group,experimental group Ⅰ and experimental group Ⅱ,10 rabbits each. Model group did not give any treatment,and the specimens were taken immediately after group divided. The experimental group Ⅰ were given wet compress with 50% magnesium sulfate. Experimental group Ⅱ were given wet compress with fresh aloe, both groups given extra plastic wrap,4 h each time,2 times per day. After 5 days specimens were taken for pathological observation. Hematoxylin-eosin staining was used to observe pathological changes of vascular intima and beneath connective tissue,transmission electron microscope to observe ultrastructural changes of vascular endothelial cells. Results:There were significant statistical differences in inflammatory effect among three groups (P < 0.001);Transmission electron microscope showed that cytoplasm mitochondria and rough endoplasmic reticulum swelling in experimental group Ⅰ and Ⅱ was less than that in model group. And the swelling in experimental group Ⅱ was less than that in experimental group Ⅰ. Conclusion:Fresh aloe and 50% of magnesium sulfate are both useful to treat phlebitis,but fresh aloe treatment is more effective than 50% magnesium sulfate.