Inclusion Criteria:  age ≥ 65 years; endoscopically proven acute nonvariceal GIB source; 48 hours after the endoscopic diagnosis and/or treatment; hemodynamically stable; the discharge of the patient is planned; hemoglobin level <10 g/dl on the day of randomisation; 24 hours after the last transfusion and no need for further transfusion; signed informed consent.  Exclusion Criteria:  known hypersensitivity to iron products (mild side effects excluded); previous diagnosis of iron overload [e.g., transferrin receptor saturation (TSAT) >50%, ferritin> 160 for women ng/ml, ferritin >270 ng/ml for men) or disorders of iron utilisation; pregnancy or breast feeding; diagnosis of iron malabsorption (at discretion of the attending clinician; e.g., severe inflammatory bowel disease, active celiac disease); chronic end stage diseases (chronic heart failure-New York Heart Association Classification class 4, liver cirrhosis with Child Pugh C score, chronic kidney disease with dialysis, chronic obstructive pulmonary disease stage 4, chronic inflammatory disease, malignancies, AIDS); active malignancies; liver cirrhosis with known varices at high risk of bleeding - endoscopic features of high risk of variceal bleeding or liver stiffness measured by transient elastography >20 kiloPascal and platelet count <150 × 10^9 cells/L; gastrointestinal tract malignancies with high risk of gastrointestinal bleeding; high risk of poor compliance or no fixed abode; myelo- or lymphoproliferative diseases; anemia not attributable to iron deficiency (sideroblastic anaemia, aplastic anaemia, haemolytic anaemia, thalassaemia, B12 vitamin or folic acid deficiency or combination of these with IDA); primary coagulation disorders (e.g. Glanzmann thrombasthenia, Von Willebrand disease, Haemophylia A, Haemophylia B); the patient will be transferred to another institute after discharge (e.g. hospital, senior care center).