Subarachnoid hemorrhage is a very dangerous disease primarily caused by the rupture of the meninges or blood vessels at the base of the skull, leading to blood entering the subarachnoid space. Clinically, the most common cause is an aneurysm, but it can also occur with some arteriovenous malformations. Subarachnoid hemorrhage can cause severe headaches, nausea, vomiting, and other complications, with severe cases leading to coma. Common complications of subarachnoid hemorrhage include, firstly, rebleeding. The probability of rebleeding is very high, and if it occurs, the disability and mortality rates of the patient significantly increase. Secondly, cerebral vasospasm, which is an important complication that can lead to severe cerebral thrombosis due to intense constriction of the blood vessels. Thirdly, it can cause secondary hyponatremia, leading to electrolyte imbalance. Additionally, complications of subarachnoid hemorrhage include increased intracranial pressure, hydrocephalus, and more.