Four patients, aged 54-84 years, presenting with life-threatening rectal bl
eeding from the superior hemorrhoidal artery, underwent percutaneous fibere
d platinum coil embolization via coaxial catheters. Pre-procedure sigmoidos
copy had failed to identify the source of hemorrhage, because the rectum wa
s filled with fresh blood. Embolization was technically and clinically succ
essful in all four patients. Subsequent sigmoidoscopy confirmed the diagnos
es in three patients as a solitary rectal ulcer, iatrogenic traumatic ulcer
ation following manual evacuation, and a rectal Dieulafoy's lesion. The oth
er case was angiographically seen to be due to a rectal angiodysplasia. Emb
olization is an effective procedure in life-threatening superior hemorrhoid
al arterial bleeding when endoscopic treatment fails, and should be preferr
ed to rectosigmoid resection.