We present the case of an 82-year-old man with a history of heart failure, mitral regurgitation, type 2 DM, hypertension, dilated cardiomyopathy and a paroxysmal atrial flutter. The patient was under treatment with Sintrom. The patient presented to the emergency department due to melenic depositions of a one day evolution and dietary vomiting. There was no rectal bleeding and the patient was admitted three months previously due to self-limited melena with a normal gastroscopy. Anemia of 8 g and an overdose of Sintrom was diagnosed. A gastroscopy was performed and a large duodenal diverticulum with a fresh clot was found that was washed. A Dieulafoy lesion was subsequently found underneath with jet bleeding, which was sclerotic with adrenaline and a hemoclip. There was a favorable evolution after correcting the coagulopathy.