Salvia miltiorrhiza cell culture extract (SCE) was shown to produce dose-dependent hypotensive response in normo-tensive rats. The mode of this hypotensive action was studied both in vivo and in vitro. This vasodepressor effect was not due to the presence of cations (potassium, calcium and magnesium) in the extract. In pharmacological antagonist studies, the hypotensive effect was shown not being mediated via the alpha-, beta-adrenoceptors, histamine receptors and autonomic ganglion; nor via direct vasodilation and diuresis. However, the vasodepressor effect was probably angiotensin- and/or bradykinin-related since captopril infusion potentiated the hypotensive effect of SCE. Furthermore, data indicated that the vasodepressor effect might be accounted for by the positive inotropic and negative chronotropic effects of SCE, the latter via its modulation of cholinergic activity.