Abstract: Acetagastrodine is a derivative of gastrodine.The consistent contraction of the spiral strips of bovine Willis arteries caused by 5-HT(10^-6M) was inhibited by both acetagastrodine and papaverine, the IC₅₀ were 995±300 μg/ml and 161±71 μg/ml, respectively. The striking contraction caused by high conentration of potassium was also antagonized by acetagasstrodine and papaverine, the IC₅₀ were 31. 53±10 . 5μg/ml and 35.18±16.6 μg/ml, respectivelyy.The strong contraction of spiral strips of rabbit aorta induced by noradrenaline 0.1μg/ml wes antagonized by acetagastrodine. The relaxing effect of aeetagastrodine on bovine Willis arteries was stronger then on rebbit erteries.