The age of onset is from 6 months to 4-5 years old (mostly from 6 months to 3 years old), with a body temperature of 38.5°C or higher, occurring at the beginning of the onset of fever or acute infectious disease (mostly seen at the beginning of the disease when the body temperature rises suddenly, 70% of which is induced by onset of fever), and the convulsions occur mostly within 24 hours after the onset of fever, excluding intracranial infections and other organic or metabolic abnormalities that cause convulsions. The clinical manifestations can be divided into two types: simple type and complex type. The characteristics of the simple type: 1. Age: between half and 4 years old, rare after 5 years old. 2, fever: generally due to acute fever at the beginning of the cold, convulsions mostly occur when the body temperature rises suddenly to 38.5 ℃ or more. 3, seizure form: a generalized seizure, manifested as loss of consciousness, generalized symmetrical tonic paroxysmal spasms, but also can be manifested as double gaze, squinting, upward turning. 4, duration: duration: lasts for a few seconds or minutes, usually no more than 15 minutes, no recurrence within 24 hours, quick return to normal consciousness after the seizure. 5.Electroencephalogram: 2 weeks after recovery of normal body temperature, EEG examination is normal. 6. Normal neurological examination before and after seizure. 7. Family history: there is a very obvious family history. The long-term prognosis of simple type of febrile convulsions is good, and there is no effect on intelligence, learning and behavior. As age increases and brain development gradually builds up, febrile convulsions generally do not occur again. Characteristics of complex type: age >6 years or <6 months, body temperature <38.5°C at the time of convulsion, abnormalities in neurological examination after the seizure, the form of seizure can be partial seizure, convulsions can last more than 15 minutes, more than 2 seizures in 24 hours, and EEG is still abnormal after 1-2 weeks of normal body temperature. The prognosis is poor, and about 1%-2% may turn into epilepsy.