We describe a patient with pheochromocytoma, which secretes dopamine. He wa
s admitted to hospital because of chronic diarrhea. After surgical resectio
n of the tumor, dramatic cessation of the diarrhea and blood pressure eleva
tion were observed, Decreased expression of dopamine beta -hydroxylase in t
he tumor was considered a possible mechanism of producing a pathophysiologi
cal concentration of dopamine. This case shows that excessive excretion of
dopamine, a vasodilative hormone, may affect blood pressure.