Bone marrow transplantation is almost one month, the withdrawal time of heparin should be judged under the guidance of the doctor, and should not be withdrawn on its own, otherwise it will cause thrombosis, and in serious cases, it will lead to a series of withdrawal reactions such as insufficient blood supply to the heart. About one month after bone marrow transplantation is the critical period after transplantation, at this time the white blood cells in the body have not grown up normally, heparin can stimulate the release of anticoagulant and fibrinolytic substances from the endothelial cells of blood vessels, so as to restore the hematopoietic as well as the immune function, therefore, heparin is a common medication after bone marrow transplantation. Heparin adverse reactions include coagulation disorders, diarrhea, rash, etc. It is contraindicated in patients who are allergic to the product and those with severe thrombocytopenia. Heparin withdrawal time after bone marrow transplantation should be based on their own recovery, under the guidance of the doctor’s judgment, do not blindly stop taking the drug on their own, so as not to affect the condition. Specific diagnosis and treatment should be carried out under the guidance of physicians.