Objective: To investigate relaxant effect of Compound Danggui decoction(DGD)-containing intestinal absorption on vascular rings of thoracic aorta in rats. Method: The everted gut sac was prepared using intestinal of rats

then was immersed into the crude extractive solution of compound DGD

the K-R solution inside the sac was collected as the intestinal absorption of DGD after 2 hours incubation. The study was performed with the model of rat isolated thoracic aorta rings in organ bath. The effect of accumulated DGD on aorta rings in resting tension

or pre-constricted with KCl

or pre-constricted with phenylephrine (PE) was observed

and were compared with nifedipine. Result: DGD had no significant effects on aorta rings in resting tension or pre-constricted with KCl. When the concentration ration of ferulic acid in DGD was cumulated to 2.48×10-3

4.96×10-3

9.92×10-3 g·L-1

it caused concentration-dependent relaxation while aorta rings were pre-constricted with PE. Nifedipine had no significant effects on aorta rings in resting tension

when the concentration ration of nifedipine was cumulated to 8.66×10-4

17.32×10-4

34.65×10-4 mmol·L-1

it caused concentration-dependent relaxation while aorta rings were pre-constricted with PE

or pre-constricted with KCl. Conclusion: Intestinal absorption of compound DGD can relax the rat thoracic aorta rings with endothelium. The results indicate that intestinal absorption containing drugs may be used to pharmacodynamic study in vitro.