Study of Incidence of Drug-induced Upper Gastrointestinal Bleeding

Inclusion Criteria: * Established diagnosis of acute upper gastrointestinal bleeding, confirmed by presence of hematemesis/ coffee ground vomiting, melena, as well as other clinical or laboratory evidence of acute blood loss from the upper gastrointestinal tract * Written informed consent provided prior the start of participation in the study. Exclusion Criteria: * Subjects who are unwilling or unable to provide informed consent.