BACKGROUND:Carboxymethyl chitosan (CMCS),a chitin derivative,has a good application performance that makes it become a safe and effective hemostatic material.OBJECTIVE:To determine the hemostatic effect of CMCS and its biosecurity properties.METHODS:(1) CMCS powder was scattered on the caudal vein and liver wounds of Sprague-Dawley rats,and the hemostatic time was recorded as experimental group,while the time for natural haemostasis of the wound was recorded as control group.(2) CMCS powder was scattered on the tail,femoral artery and liver wounds of ICR mice,and the hemostatic time was recorded as experimental group,while the time for natural haemostasis of the wound was recorded as control group.(3) CMCS,Sodium dodecyl sulfate solution and distilled water were respectively applied on the skin of albino rabbits in a skin irritation test.(4) A delayed-type hypersensitivity test of CMCS was carried out by intradermal injection of CMCS in guinea pigs.(5) An intradermal irritation test was carried out by subcutaneous injection of normal saline containing CMCS and normal saline,respectively.Another intradermal irritation test was carried out by subcutaneous injection of the supernatant of CMCS olive oil extract and olive oil,respectively.RESULTS AND CONCLUSION:(1) Compared with the control group,the hemostatic time for caudal vein and liver wounds were significantly shortened in the Sprague-Dawley rats in the experimental group (P ＜ 0.01).(2) Compared with the control group,the time of hemostasis on the tail,femoral artery and liver wounds was significantly shortened in the ICR mice in the experimental group (P ＜ 0.05 or P ＜ 0.01).(3) The CMCS had no irritation to the skin of albino rabbits and no allergic reaction to the skin of guinea pigs.To conclude,the CMCS has good hemostatic effect on the wound in Sprague-Dawley rats and ICR mice,and has no skin irritation,allergic reactions and intradermal irritation reactions in albino rabbits and guinea pigs,which is a relatively safe hemostatic material.