Formaldehyde poisoning will show the following manifestations: 1. symptoms of upper respiratory tract irritation, manifested as sore throat, dry itch, dryness, hoarseness, sneezing, coughing, etc. 2. symptoms of pneumonia, such as bronchitis, manifested as severe coughing, chest tightness, chest pain, difficulty in breathing. 3. pulmonary edema, manifested as shortness of breath, as well as choking and coughing, nausea. 4. allergic reactions, patients develop allergic purpura, bronchial asthma, contact dermatitis. 5. 5. laryngeal spasm, laryngeal edema, manifested as asphyxia, or even sudden death. 6. changes in the central nervous system, with dizziness, headache, drowsiness, and peripheral weakness. 7. other malignant diseases can be induced, including the appearance of malignant tumors, genetic mutations, etc.