There may be co-factors, like genetic tendencies and smoking which are contributory. H. pylori can trigger off an inflammatory reaction as the result of the release of ammonia. The bacteria produces an enzyme, urease, which enables it to produce large amounts of ammonia. The ammonia is protective to H. pylori since it neutralizes the largely acidic environment in which it finds itself and, therefore, enables it to continue colonizing the gastric mucosa. Bleeding is a frequent complication of GI disease.
Hematemesis is the vomiting of blood.
Hematochezia is the passage of bloody stools. It is the result of partially digested blood. It is important to keep in mind that ingestion of iron, charcoal, Pepto bismol and licorice can turn the stools black. An examination of the pattern of blood in the stools can be diagnostic of the location of the bleed in the GI tract. Bright red blood only is due to bleeding in the rectum or lower sigmoid.