Brain aneurysms are called “untimely bombs” because they do not necessarily “explode,” and it should be said that a significant number of aneurysms can coexist peacefully with people throughout their lives. The autopsy rate of cerebral aneurysms is reported to be quite high, ranging from 0.2% to 4.5%, while the annual incidence of spontaneous subarachnoid hemorrhage is only 10.5 per 100,000. However, a “bomb” is a “bomb,” and when it explodes, the consequences are often catastrophic. To answer the question of when an unruptured aneurysm is likely to rupture and bleed, it is important to understand the risk factors for the formation, development and rupture of unruptured aneurysms, which include modifiable and non-modifiable risk factors. Smoking and hypertension are modifiable factors, while age, gender and genetics are non-modifiable factors. The American Heart Association and American Stroke Association guidelines for the management of unruptured cerebral aneurysms (2015 edition) make the following recommendations: 1. Given that smoking increases the risk of unruptured aneurysm formation and rupture, patients should be informed of the importance of smoking cessation; 2. Given that hypertension may promote the development and rupture of cerebral aneurysms, patients with unruptured aneurysms should monitor their blood pressure and systematically and regularly treat their hypertensive disease; 3. Follow up findings Patients with a history of aneurysmal subarachnoid hemorrhage suggest that unruptured aneurysms at other sites may also have a higher risk of hemorrhage and should be treated with active surgery; 5. Palsy due to unruptured aneurysms is often a precursor to rupture and is an indication for early treatment. A foreign researcher distributed questionnaires to 250 surviving patients with subarachnoid hemorrhage (mean age 54 years) and asked about the patients’ exposure to 30 potential triggers one hour before bleeding, and finally counted the eight most significant triggers, including drinking coffee (10.6%), strenuous activity (7.9%), blowing nose (5.4%), sexual behavior (4.3%), forceful bowel movement ( 3.6%), cola drinking (3.5%), shock (2.7%), and anger (1.3%). All eight triggers can increase blood pressure in a short period of time and may be the direct cause of aneurysm rupture.