Abstract: Objective To determine the effects of active fraction of Angelica sinensis on antioxidant and red cell immune adherence function in cool stress mice.Methods The water extraction and alcohol precipitation method were adopted to obtain 3 active fractions of Angelica sinensis.Seventy-two healthy SPF mice were randomly divided into control group(M), model group(K), Angelica sinensis active fraction A treatment group(A), Angelica sinensis active fraction B treatment group(B), Angelica sinensis active fraction C treatment group(C), Rhodiola rosea treatment group(T).The mice were administered corresponding treatment by gavage for 14 days.Control mice were given normal saline in same volume.On the 10th day of the treatment, 3 minutes forced cold water(8±2 ℃)swimming 0.5 hour after gavage treatment was used as a stressor to all mice excepted control mice once a day for 5 days.On the 14th day of the treatment, all mice were decapitated and duration of gasping and heart beat after decapitation were investigated.And the blood samples were collected to determine erythrocytic immune function and the content of superoxide dismutase(SOD)and malondialdehyde(MDA)in blood serum.Immune organ weight of the mice was observed and the level of glutathione peroxidase(GSH-Px)in immune organ tissue was determined.Results Compared with the control group, duration of gasping(20.75±3.11 s)and heart beat(51.63±4.10 s)after decapitation, thymus(2.19±0.47 mg/g)and spleen index(2.62±0.61 mg/g)decreased significantly in the model group(P<0.05).The content of GSH-Px in thymus and spleen(19.16±2.15, 1.65±0.58 U/mgpro), the level of SOD(173.53±27.39 U/mL), and red blood cell C 3b receptor(RBC-C3bR)rosette rate, red blood cell immune complex(RBC-IC)rosette rate decreased significantly, but the level of MDA in serum(12.02±0.62 nmol/mL)significantly increased in the model group(P<0.05).Experiment tests showed that the duration of heart beat after decapitation prolonged, the thymus and spleen index increased in the mice of group A, B, and C compared with those of the model group(P<0.05 for all).The content of GSH-Px in thymus in the mice of group B(5.32±2.47 U/mgpro)and group C(3.76±1.58U/mgpro), and RBC-IC rosette rate in both groups increased compared with those of the model group(P<0.05 for all).The level of serum SOD(220.03±36.33 U/mL), the content of GSH-Px in spleen(49.49±1.77 U/mgpro), and RBC-C3bR rosette rate were obviously increased but MDA(7.95±1.55 nmol/mL)decreased in group B compared with those of the model group(P<0.05 for all).Conclusion Active fraction B and C of Angelica sinensis could enhance the antioxidant ability and strengthen the erythrocytic immune function in cool stress mice.