Objective: To demonstrate the pharmacodynamic interaction in tonifying blood of couplet medicines of Angelicae Sinensis Radix and Carthami Flos by comprehensive index method and three-dimensional response surface method. Method: Based on mouse blood deficiency model induced by injection of acetylphenylhydrazine (APH) and cyclophosphamide (CTX)

the effect of this couplet medicines with different proportions (1:0

4:1

2:1

3:2

1:1

2:3

1:2

1:4

0:1) and different concentrations on the peripheral blood indexes and organ indexes were observed.Then all indexes were integrated and analyzed by relative equation.The three-dimensional response surfaces were gained by Matlab R2010a software. Result: When they were used singly

the best doses of Angelicae Sinensis Radix and Carthami Flos were 7.80

0.52 g·kg-1·d-1

respectively.Most dose(about 50%) of this couplet medicines exhibited addition action

followed by antagonism

and little dose (0.5-1.2 g·kg-1·d-1 of Angelicae Sinensis Radix and 0-0.5 g·kg-1·d-1 of Carthami Flos) had synergetic effect. Conclusion: The range of synergetic effect of this couplet medicines on tonifying blood is little

and the intensity is not obvious

but it has antagonism in a certain amout.