If someone close to you suddenly has a severe headache of unknown origin, sometimes accompanied by nausea and vomiting, or even confusion, you must be careful because the patient may have had a subarachnoid hemorrhage. The most common cause of primary subarachnoid hemorrhage (SAH) is bleeding from a ruptured intracranial aneurysm, which accounts for about 80-90% of cases. The disease is very dangerous, with a mortality rate of more than half, and a significant proportion of patients who are lucky enough to survive are left with neurological deficits such as limb paralysis, inability to speak, and mental abnormalities. The greatest risk is that it may rupture and bleed again at any time, and if it does, the mortality rate will be even higher. This places a heavy burden on society and families. The most typical symptom of subarachnoid hemorrhage caused by aneurysm is sudden and severe pain, which is often described as “more painful than giving birth” and “the most painful ever” by patients. This pain is often accompanied by nausea, vomiting, “stiff neck”, convulsions or coma. So what should you do if you encounter this situation. The first step is to keep the patient lying down and minimize activity. Then quickly call 120 and take the patient to the nearest hospital. A CT head examination can confirm the diagnosis of subarachnoid hemorrhage. A cerebrovascular examination (e.g., head CTA, MRA) can initially screen for intracranial aneurysm, and cerebral angiography is the gold standard for aneurysm diagnosis. If an intracranial aneurysm is diagnosed, prompt and effective treatment is needed immediately, and if there are no absolute contraindications to surgery, surgery should be performed as soon as possible. The treatment of subarachnoid hemorrhage requires a mature medical team to select the appropriate treatment for the patient’s condition. Patients should be referred to a medical unit with adequate qualifications and treatment experience if possible to avoid delaying the condition. The Neurosurgery Cerebrovascular Disease Unit of the hospital is one of the few medical units in China that specializes in the treatment of cerebrovascular disease, and its microsurgery and interventional embolization techniques are the first-class in China. We can also combine microsurgical techniques with interventional techniques to effectively treat various complex intracranial aneurysms. We treat nearly 1,000 cases of subarachnoid hemorrhage due to aneurysm each year with definite results.