Formaldehyde damage to the human body is mainly on the eyes, skin, respiratory system, nervous system, immune system and other damage. 1. Eyes: the conjunctiva of the eye is sensitive to formaldehyde vapor, long-term exposure will appear dry eyes, tearing, photophobia, pain and other symptoms, serious cases will appear visual impairment. 2. Skin: If the skin is exposed to formaldehyde for a long time, the skin will be strongly stimulated by rashes, dryness, redness, itching and other symptoms, and even local skin tissue necrosis. 3. Respiratory system: inhalation of gases containing formaldehyde will lead to laryngeal edema, bronchospasm, the patient will feel breathless, coughing, chest tightness, long-term exposure may also cause chronic pneumonia, asthma and other causes of lung function decline. 4. Nervous system: inhalation of formaldehyde can lead to damage to the nervous system, patients experience dizziness, headache, fatigue, insomnia, drowsiness and other symptoms. 5. Immune system: long-term inhalation of formaldehyde can damage the immune system, resulting in impaired immunity, patients are prone to repeated colds, fever and other symptoms. Formaldehyde belongs to genotoxic substances, and even lead to the occurrence of tumors, especially leukemia, lymphoma and so on. In addition, formaldehyde also affects the reproductive system and endocrine system, showing damage to the function of various organs, which is very harmful to human body. Formaldehyde is a gas with a strong irritating odor, usually need to pay attention to stay away from formaldehyde over the environment.