A case of ruptured pheochromocytoma is presented, the pathophysiology discussed, and the literature reviewed. Evidence is presented that the use of alpha-adrenergic blockade in general, and phentolamine in particular, may predispose to this complication. Twelve cases of massive hemorrhagic necrosis with or without rupture were found in the literature, including the present case. Six had no operation; one survived. Six had immediate operation; 4 survived. An additional case of hemorrhage into a small pheochromocytoma following phentolamine is presented. This tumor was neither ruptured nor massively necrotic, but the case supports the hypothesis that alpha-adrenergic blockade may cause hemorrhage within the pheochromocytoma.