Formaldehyde is a volatile toxic gas, and after poisoning, it is divided into acute and chronic poisoning. In case of acute poisoning, the gas irritates the eyes and respiratory tract, causing dry pain and tears in the eyes, irritating dry pain in the nose and throat, and an irritating cough. If laryngeal edema or pulmonary edema is caused, breathing difficulties may also occur, which can lead to suffocation and death in severe cases. In addition, neurological symptoms may occur, with dizziness, nausea, and vomiting. If more severe, coma, convulsions, or even death from respiratory and cardiac arrest due to central respiratory and cardiac depression can occur. Chronic formaldehyde poisoning can manifest as symptoms of neurological weakness, such as memory loss, frequent insomnia and dreaminess, or uncoordinated arms and legs, dizziness and other symptoms, which can seriously affect the hematopoietic system and lead to anemia, or even leukemia in more serious cases.