When children have nosebleeds, it is necessary to comprehensively determine whether they suffer from blood system diseases according to specific symptoms, blood routine, bone marrow puncture and other tests. 1. Specific symptoms: normal nosebleeds are usually caused by dry nasal mucosa, trauma, etc., with small amount of bleeding which can be stopped by compression; if nosebleeds are caused by hematologic diseases, the amount of bleeding is usually larger, and symptoms such as pallor, fatigue, and lack of mental ability may occur at the same time. 2. Blood routine: Normal blood routine values are within the standard range; if it is a blood system disease, the blood routine performance will usually show more obvious abnormalities. Therefore, if the baby only has symptoms of nosebleed but normal blood counts, it is less likely that he/she is suffering from blood system diseases. 3. Bone marrow aspiration: Normal bone marrow aspiration result can see normal morphology of primitive cells and even distribution of cells in various stages of differentiation, however, bone marrow aspiration result of hematologic diseases may have irregular morphology of primitive cells, and the number of cells may be significantly increased or significantly decreased. Therefore, when a child has a nosebleed, parents should first rule out bleeding due to dry air, trauma, or injury to the nasal mucosa. If nosebleeds occur frequently and the effect of pressure to stop bleeding is not good, it is generally recommended to consult a doctor in time to check the blood routine, blood smear, and if necessary, bone marrow aspiration, to clarify whether there is a hematologic disease, and symptomatic treatment under the guidance of the doctor.