The degree of carbon monoxide poisoning can be divided into three levels: mild poisoning, moderate poisoning and severe poisoning, which are often graded according to laboratory indicators and clinical symptoms. 1. Laboratory indicators: the degree of carbon monoxide poisoning can be graded according to the concentration of carboxyhemoglobin. If the patient’s carboxyhemoglobin concentration is 10% to 20%, it is mild poisoning. If the concentration reaches 30% to 40%, it is moderate poisoning. When the concentration reaches 40% to 60%, it is severe poisoning. 2. Clinical symptoms: After carbon monoxide poisoning, if the patient has symptoms such as dizziness, nausea and vomiting, it is generally mild poisoning. If the above symptoms are accompanied by euphoria, motor disorders and hallucinations, it is generally a moderate poisoning. If there are symptoms of convulsions, hypotension, arrhythmia or even respiratory failure, the poisoning is considered severe. If symptoms of carbon monoxide poisoning occur, patients should stay away from the poisoned environment and seek medical treatment in time.