Sudden clinical illnesses are common, mostly seen in cardiovascular diseases and respiratory diseases, etc. In clinical treatment, the primary purpose of first aid is to maintain the patient’s vital signs stable and to guarantee the stability of respiratory and circulatory functions. For example, for patients with seizures, they should be given airway function protection, either by making the patient lie flat with the head to the side or by giving the patient a lateral lying position placement, while untying the patient’s collar and sash to achieve the purpose of keeping the airway open. In the case of obvious secretions, they should be wiped in time to avoid aspiration, which can lead to serious complications such as aspiration pneumonia and asphyxia. For sudden anterior heart pain with numbness and abnormal sensation in the left shoulder and left arm, consider whether the patient has angina pectoris. For patients with a previous history of coronary heart disease and the presence of related high-risk factors such as hypertension and hyperlipidemia, the patient should be told to stop related exertion immediately and given rest. If possible, sublingual nitroglycerin can be given at intervals of 3-5 minutes, but not more than 3 times. If the clinical symptoms are not relieved after the patient is given rest and the relevant medication is administered, the patient should promptly call 120 for the appropriate medical treatment. In conclusion, in the treatment of sudden illness, the patient’s respiratory and circulatory function should be stabilized to improve the chances of saving the patient’s life, and the patient should be contacted for medical treatment in a timely manner.