The causes of nasal bleeding mainly include two types: local causes and general causes. Local causes are less, mainly including nasal trauma, inflammation of nasal cavity, tumour of nasal cavity and sinuses, deviation of nasal septum; general causes give rise to more cases of nasal hemorrhage, chiefly including elevation of vascular arterial pressure and elevation of vascular venous pressure due to some diseases, or increased fragility of blood vessels and dysfunction of blood coagulation. For instance,acute febrile infectious diseases like influenza, measles,hemorrhagic fever, typhoid and malaria, cardiovascular diseases like hypertension, arteriosclerosis and cardiopathy, hematopathy, dystrophy or avitaminosis, chronic visceral diseases of the liver, spleen and kidney, rheumatic fever as well as during menstrual period and at pregnant stage, etc. Nasal bleeding easily occurs in all the above cases.

(A) Partial reason
1. Trauma
2. Barotrauma
3. deviation of nasal septum, perforation of nasal septum, also often accompanied with epistaxis symptoms.
4. Inflammation: 1) non-specific inflammation: dry rhinitis, atrophic rhinitis, acute rhinitis, acute maxillary sinusitis due to epistaxis, 2) specific infection: nasal tuberculosis, diphtheria nose, nasal syphilis, nose bleeding due to mucosal ulceration.
5. Tumors
6. Others: Nasal foreign body, nasal leeches can cause heavy bleeding again. In the plateau region, more people suffer dry rhinitis due to low relative humidity. This is an important reason for the region epistaxis.

(B) Systemic reasons
1. Blood diseases: 1) platelet volume or quality anomalies, 2) anomalies of clotting mechanism,
2. Acute infectious diseases,
3. Cardiovascular Disease: 1) arterial pressure is too high: such as hypertension, atherosclerosis, nephritis, eclampsia with hypertension and other problems, 2) increase of venous: such as mitral stenosis, thoracic or mediastinal and neck huge mass , emphysema, pulmonary edema and bronchial pneumonia.
4. Vitamin deficiency: Calcium deficiency, such as Vitamin C, K, P and trace elements is prone to nosebleeds.
5. Chemicals and poisoning: phosphorus, mercury, arsenic, benzene poisoning can cause damage to the hematopoietic system function epistaxis. Long-term use of salicylic acid drugs can cause bleeding easily.
6. Endocrine disorders: compensatory menstruation, threatened epistaxis often occurs in puberty, usually caused by blood estrogen levels decrease, due to nasal blood vessels to dilate,
7. Hereditary hemorrhagic telangiectasia, liver, kidney and other chronic diseases and rheumatic fever also may be associated with nasal bleeding.