The etiology of subarachnoid hemorrhage is more diverse, and the common clinical manifestations are headache, reflex vomiting, which may be accompanied by coma, impaired consciousness, epilepsy, and convulsions. The causes of headache due to hemorrhage are as follows: 1) blood enters the subarachnoid space and stimulates the meninges; and toxic products stimulate the transparent structures of the brain causing headache; 2) massive hemorrhage causes headache due to increased cranial pressure; 3) cerebrospinal fluid reabsorption is impaired and accumulates excessively in the subarachnoid space, causing hydrocephalus causing headache attacks.