The mortality from upper gastrointestinal (GI) tract bleeding has remained constant at 10% during the past 40 years. Many drugs may precipitate upper GI tract bleeding by disrupting the gastric mucosal barrier. Aspirin-induced injury to the gastric mucosa and GI tract bleeding have been documented in many studies; some of the mechanisms involved are known, but others are still being investigated. An approach to the bleeding patient is suggested; initial resuscitation, history taking, physical examination, determination of bleeding levels, and diagnostic procedures to determine the cause of bleeding are reviewed. Also described are available therapies for GI tract bleeding-gastric lavage, drug therapy, endoscopic control, electrocautery, thermal probe, tissue adhesive, and laser photocoagulation. The merits of the argon laser and the neodymium-yttrium aluminum garnet laser (both still in experimental stages) are described and compared. No pharmacologic or endoscopic therapies for upper GI tract bleeding have been proved effective.