During bone marrow transplantation pretreatment high-dose cyclophosphamide chemotherapy, it can be treated by taking hemostatic drugs, electrocautery for hemostasis, blood transfusion, and applying acid-suppressing and stomach-protecting drugs under doctor’s guidance. If gastrointestinal bleeding occurs during pretreatment high-dose cyclophosphamide chemotherapy for bone marrow transplantation and the amount of bleeding is relatively small, it can be treated by taking hemostatic drugs, such as Anluo blood, or electrocautery hemostasis under endoscopy under the guidance and advice of a doctor. If the situation of gastrointestinal bleeding is more serious, blood routine and coagulation function monitoring should be carried out in time, and blood transfusion treatment should be carried out if necessary. Cyclophosphamide has a strong irritation, easy to cause stress ulcers, it may cause the phenomenon of gastrointestinal bleeding, you can take omeprazole under the guidance of the doctor’s advice to inhibit acid and protect the stomach for treatment. The occurrence of this situation, it is recommended that patients do not take drugs privately to avoid adverse effects, patients should promptly explain the situation with the doctor, and under the guidance of the doctor for treatment.