Basophils are one of the many types of white blood cells. High basophils usually refer to a high basophil count. The cause of high basophils alone cannot be determined, but needs to be combined with clinical manifestations and other laboratory test values. High basophils are most commonly associated with the following diseases: 1. Metabolic and inflammatory diseases: Clinical conditions that commonly cause high basophils are metabolic reactions and inflammatory diseases, usually accompanied by increased white blood cells and neutrophils in addition to high basophils. For example, upper respiratory tract infections, heavy metal poisoning, ulcerative colitis, rheumatoid arthritis, urticaria, anaphylaxis, and allergic reactions to food and drugs; 2, myeloproliferative diseases: chronic granulocytic leukemia, chronic basophilic leukemia, acute promyelocytic leukemia, true erythroblastosis, primary thrombocytosis, primary myelofibrosis, etc. 3, endocrine diseases: diabetes mellitus, hypothyroidism, or long-term estrogen therapy, may also appear high basophils; 4, malignant tumors: some patients with malignant tumors may also have high basophils, commonly metastatic cancer and Hodgkin’s lymphoma patients. In addition, patients with systemic mastocytosis and tuberculosis can also have high basophils. If high basophils are found during physical examination, blood smear and bone marrow examination are recommended to identify the primary disease, and treatment should be given for different causes of high basophils, and the basophil count will return to normal when the disease is in remission.