If an elderly person experiences sudden fainting, the specific causes are as follows: First, if the elderly person has a previous history of cerebrovascular disease, be highly suspicious of cerebrovascular accidents, such as ischemic stroke, hemorrhagic stroke, and transient cerebral blood supply insufficiency episodes, all of which are associated with the possibility of fainting. Second, for older adults with a previous history of coronary heart disease, fainting should be considered for the presence of acute coronary syndrome, typical arrhythmias, and acute myocarditis. Then, for older adults with a previous history of diabetes mellitus in case of sudden fainting, consider hypoglycemic coma, diabetic ketoacidosis, hyperosmolar coma, and lactic acidosis. In addition, older adults may also faint if they experience aura heat stroke in summer under high environmental factors. Finally, fainting can also occur in the case of acute gas poisoning, drug poisoning, and food poisoning.