Brain cysts can be dangerous, but they must be treated on a case-by-case basis. Brain cysts are a very broad concept, divided into arachnoid cysts, pituitary cysts or pineal cysts, and even cysts elsewhere. In many cases there are no abnormal clinical symptoms and they are not detected, occasionally they are found only during physical examination, which is not particularly dangerous. The most fearful thing is that the rapid increase of the cyst and the compression of the brain tissue will produce very obvious clinical symptoms. Although there is a certain amount of compensatory space in the skull, the compensatory mechanism is not sufficient and often very obvious effects are formed, such as severe headache, dizziness, even numbness and weakness of the limbs, speech dysfunction, which may cause epilepsy and the corresponding symptoms of endocrine dysfunction. If this is the case, it is a more dangerous situation and needs to be actively treated accordingly.