Fainting is mostly caused by loss of balance or loss of consciousness due to transient ischemia of the brain, and many diseases can lead to both of the above situations.1. Fainting can be seen in posterior circulation ischemia, due to poor blood supply to the posterior circulation vessels, ischemia of the brainstem or cerebellum can cause fainting, and can be accompanied by other neurological deficits in severe cases.2. Coronary heart disease, such as premature cardiac arrest, sick sinus node syndrome and severe angina, due to reduced ejection of blood from the heart can also lead to reduced blood supply to the brain, and in severe cases, fainting can occur. Premature cardiac arrest, pathological sinus node syndrome and severe angina pectoris, due to the reduction of blood ejection from the heart can also lead to a reduction in the blood supply to the brain, when serious, people will fainting and fainting. 3, fainting can also be seen in diabetes, hypoglycemia, due to the low blood glucose leading to a reduction in the brain’s sugar and oxygen, people can also fainting, before the onset of the onset of the heart will be accompanied by panic and other symptoms.