Gas poisoning, also known as carbon monoxide poisoning, is classified as mild, moderate or severe according to the symptoms of poisoning, and the characteristic manifestations of each degree are different. 1. The characteristic manifestations of mild poisoning are dizziness, headache, tinnitus, vertigo, nausea, accompanied by violent vomiting as symptoms. 2. The main characteristic manifestations of moderate symptoms are flushed face, cherry red lips, rapid heart rate, cardiac arrhythmia, excessive sweating, increased generalized muscle tone, muscle tremor, unsteady gait, and sometimes delirium. 3. The main characteristic manifestations of severe gas poisoning are severe flushing, increased respiration, unconsciousness, loss of orbital reflex and pupil-to-light reflex.