1. In the rabbit and the dog, the blood pressure response to water extract and methanol extract obtained from Atractylodes rhizoma alba was investigated. 2. Water extract and methanol extract, when administered into the rabbit and the dog by the route of vein, produced fall of the blood pressure. 3. The depressor response of the rabbit to water extract and methanol extract was not affected by Avicel^ⓡ, propranolol and atropine. 4. The depressor response by water extract and methanol extract in the rabbit was not affected by guanethidine, but water extract and methanol extract produced elevation of blood pressure in this rabbit. 5. Pretreatment of rabbit with chlorisendamine or phenoxybenzamine weakened the depressor response to water extract and methanol extract, and the both extracts produced secondary elevation of blood pressure in this rabbit. 6. The pressor response of the chlorisondamine-treated rabbit to water extract and methanol extract was not affected by atropine. 7. Water extract decreased the pressor action of tyramine and depressor action of pilocarpine and isoproterenol, but did not affect the blood pressure response of nor einephrine, angiotensin and dimethylpehnyl piperazinium iodide (DMPP).