An elderly obese male with a lengthy history of melanotic stools was admitted and was shown to have a posterior duodenal ulcer by endoscopy. He became obtunded and developed infected ascites. Because of his obesity, ascites, and inability to cooperate, the GI radiologist felt that a Gastrografin upper GI series would not be helpful. We therefore gave the patient 99mTc-labeled sulfur colloid and tap water through his nasogastric tube. We were able to clearly image a site of perforation at the duodenal bulb communicating with the lesser sac.