Background: For patients with severe upper gastrointestinal (UGI) hemorrhage, risk stratification for rebleeding or endoscopic hemostasis has been based on visually defined endoscopic stigmata of hemorrhage for more than 40 years. These are imperfect, because there is significant interobserver variation and the investigators were previously unable to detect underlying vessel blood flow, which is directly related to the risk of rebleeding. Doppler ultrasound endoscopic probes (DEP) are relatively new in the US and can detect underlying lesion blood flow. However, few patients with severe UGI hemorrhage have been studied with endoscopic doppler ultrasound probe in the US and none in VA's. The Center for Ulcer Research and Education (CURE)/VA GI Hemostasis Research Group will perform prospective randomized studies at the West Los Angeles VA and University of California Los Angeles (UCLA) Ronald Reagan Medical Centers to define the role of DEP in management of severe UGI hemorrhage.