Hematologic diseases have become an “ice” in the medical field because of their complexity, intractability, difficulty in treatment and high mortality rate. There are many causes of blood disorders, and clinical observations have revealed that a small number of people have blood disorders caused by improper use of medications. Understanding the relationship between these drugs and blood disorders is extremely important for the prevention of certain blood disorders. 1, aplastic anemia Most of the commonly used anti-cancer drugs have the side effect of inhibiting bone marrow hematopoiesis and are dose-related, such as adriamycin, cytarabine, cyclophosphamide, phenylalanine nitrogen mustard, etc. Some drugs are not harmful to most people at normal doses. However, they can cause aplastic anemia in some people (not much related to the dose), such as chloramphenicol, sulfonamides, etc. 2, thrombocytopenia and hemostatic dysfunction Some drugs can cause poor bone marrow regeneration, direct destruction of platelets or immune thrombocytopenia. Commonly used drugs include rifampin, antipyretic and analgesic drugs, sulfonamides, antidiabetic drugs, sedatives, dihydrocoumaric acid, digoxin, methyldopa, ethosuximide, methotrexate, vincristine, erythromycin, etc. Some drugs can cause platelet dysfunction and affect the hemostatic function. For example, anti-inflammatory pain, aspirin, bicuculline, etc. When platelet reduction or dysfunction occurs, skin purpura, mucous membrane bleeding and internal bleeding can occur in serious cases. 3, allergic purpura Due to allergy to certain drugs, causing increased permeability and fragility of capillary walls, allergic purpura occurs, often manifested as skin purpura, but also abdominal pain, joint pain and other symptoms. The more common drugs are antibiotics, sulfonamides, antipyretic and analgesic drugs such as streptomycin, isoniazid, aspirin, anandamide, etc. 4, leukopenia due to the role of certain drugs on the bone marrow, the inhibition of hematopoietic function or lead to maturation disorders, etc., can cause leukopenia, neutropenia, serious cases can lead to granulocyte deficiency and serious infections, life-threatening. The more common drugs are chloramphenicol, pau d’arco, anti-inflammatory pain, sulfonamide, quick-acting cold capsules, meprobamate, chloroquine, and the treatment of hyperthyroidism drugs such as organic arsenic. 5, anemia The main drugs that cause anemia are aminosalicylic acid, sodium phenytoin, antiepileptic drugs, antimalarials, sulfonamides, antituberculosis drugs, as well as folic acid, carbamazepine, etc. 6.Acute leukemia It is now known that alkylating agents, chloramphenicol, topoisomerase II inhibitors, bismorpholine, ethylimine, etc. can cause acute leukemia (blood cancer), and patients can develop anemia, fever, bleeding, enlarged liver, spleen and lymph nodes and other symptoms, which are life-threatening. Some drugs have a significant effect on the blood, but the patient is not sure until they are applied. And once the damage to the blood is caused, it is often difficult to treat. Therefore, patients should never use the above-mentioned drugs indiscriminately and should use them according to medical advice when they are ill.