High basophils may be due to allergic diseases, blood diseases, tumors and so on. 1. Allergic diseases: hypersensitivity reactions due to drugs, food, inhalants, leading to allergic diseases. Peripheral blood basophilic granulocyte progenitor cells are increased, thus causing peripheral blood basophilia. For example, ulcerative colitis and rheumatoid arthritis. 2. Blood diseases: for example, chronic granulocytic leukemia, which may be caused by ionizing radiation, exposure to hair dyes, etc., leading to chromosome 9 and 22 abnormalities, causing excessive cell proliferation and basophilia. 3. Tumor: when there is malignant tumor, especially metastatic cancer, the proportion of basophils in peripheral blood increases under the influence of tumor. When the basophils are high, it is recommended to consult a doctor in time, follow the doctor’s instruction for further examination, clarify the cause with the help of doctor, and carry out targeted treatment or therapy.