A 66-year-old Asian man with melena was admitted to our hospital. The patient had had loose tarry stools two times a day (about 300 g each time) for 2 days without hematemesis before he was admitted. He did not complain about any abdominal pain or jaundice but felt dizzy and weak. He had coronary heart disease with a coronary stent placed 2 years previously and had been prescribed an ongoing therapy of aspirin 100 mg per day. The patient denied any positive family history. Upon admission, his temperature was 36.4°C, heart rate was 101 bpm, blood pressure was 112/74 mmHg, and respiration rate was 20 breaths/min. The patient was conscious and anemic looking, and bowel sounds were active. His abdominal color Doppler ultrasound was normal. Blood analysis revealed a total white blood cell count of 12.58 × 109/L, red blood cell count of 2.69 × 1012/L, and hemoglobin of 82 g/l. The fecal occult blood test was (+). Liver and kidney biochemical and function tests were normal. The coagulation test revealed normal. After admission, the patient had nothing per os and received intravenous fluid resuscitation and proton pump inhibitors. An urgent upper gastrointestinal endoscopy was performed and revealed fresh red blood clots covering the duodenal papilla, with continued oozing blood from its basilar part, classified as Forrest Ib. The endoscopy was performed again with a duodenoscope for treatment. We planned to expose the opening of the duodenal papilla by removing the clots, sliding a catheter into the common bile duct and placing a plastic stent, and then clamping the hemorrhagic spot with titanium clips. During the procedure of locating the opening of the duodenal papilla after the clots were removed, the hemorrhage got worsened and began to present pulsating bleeding (). Electrocardiography (ECG) monitor showed that the patient’s heart rate rose to 120–130 bpm and blood pressure dropped to 79/ 47 mmHg. The hemorrhage had to be stopped as soon as possible. We informed the patient’s son, who was the statutory agent of the patient, of the urgent situation and possible complications of clamping the bleeding spot without placing a bile duct stent previously, such as acute pancreatitis, obstructive jaundice, and acute obstructive suppurative cholangitis. With the consent, two titanium clips were inserted to clamp the bleeding site on the duodenal papilla. The 11 o’clock position and 1 o ‘clock position of the duodenal papilla were avoided as far as possible during the operation. The bleeding stopped immediately after the clips were placed (). With further rapid intravenous fluid resuscitation and erythrocyte transfusion, the patient’s heart rate and blood pressure went normal. However, the patient complained of epigastric pain and abdominal distension 14 h later after the endoscopy. Abdominal computed tomography (CT) scan (no contrast was used) showed diffuse enlargement of the pancreas and extensive peripancreatic exudation (). Other abnormal laboratory examination results were shown below: c-reactive protein 114.7 mg/l, serum amylase 2,368 U/l, aspartate aminotransferase 79 U/l, white blood cell count 21.16 × 109/L, red blood cell count 3.38 × 1012/L, hemoglobin concentration 104.00 g/l, calcium 1.60 mmol/l, creatinine 133 μmol/l, lactate dehydrogenase 757 U/l, and α-hydroxybutyric acid 524 U/l. Acute pancreatitis was diagnosed. Endoscopy was performed immediately to remove the titanium clips. There was no re-bleeding after the clips were removed. The duodenal papilla was clearly observed, showing a vessel stump located at the 9 o ‘clock position (). Then, the final diagnosis of the hemorrhage was massive upper gastrointestinal bleeding caused by a Dieulafoy’s lesion on the duodenal papilla. After further treatment of pancreatitis for 12 days, the related symptoms and indicators of pancreatitis were improved and no more bleeding occurred. The patient was discharged from the hospital on the 14th day and followed for 6 months with no recurrence.