Dieulafoy's lesions, very rare in the duodenum, are considered uncommon causes of gastrointestinal bleeding and occur from pinpoint non-ulcerated arterial lesions. We report a case of Dieulafoy's lesion of the duodenum, in which a first diagnostic approach by using endoscopy and angiography was not successful; then, due to a high operative risk, we performed an "adjuvant" embolization of the gastroduodenal artery with the aim of reduce the flow through the artery, allowing the endoscopic localization of the site of bleeding and subsequent effective treatment. To our knowledge, this is the first case reported in the literature, in which, without aetiological diagnosis, an "adjuvant" embolization of the gastroduodenal artery was performed with the aim of reduce the blood flow in the duodenal wall, permitting an easier endoscopic diagnosis of Dieulafoy's duodenal lesion and successful treatment with laser coagulation.