Objective:The aim is to study the anticoagulative effect of glaucocalyxin A.Methods:The effects of glaucocalyxin A on capillary vessel coagulation time and the tail point place blood time were measured.The influence of glaucocalyxin A on thrombin time (TT),prothrombin time (PT),activated partial thromboplastin time (APTT) and plasma recalcification time (PRT) of mice was observed.The influence of glaucocalyxin A on rabbit plasma TT,PT,APTT,and PRT was detected in vitro.Results:Glaucocalyxin A significantly lengthened the capillary vessel coagulation time and the tail point place blood time of mice.The TT,PT,APTT and PRT of mice were prolonged after they were treated with glaucocalyxin A.In vitro,TT,APTT and PRT of rabbit were prolonged by glaucocalyxin A.Conclusion:Glaucocalyxin A has anticoagulative effect.