4. Subjects with high gastrointestinal bleeding risk, including the following conditions: local active ulcer lesions with positive fecal occult blood test (++); history of black stool, or vomiting blood in the past 2 months;unresected primary lesion in stomach with positive fecal occult blood test (+), ulcerated gastric carcinoma with massive alimentary tract bleeding risk judged by PIs based on gastric endoscopy result;