The dangers of a persistent fever from a cold include dehydration, convulsions, and cerebral edema. 1. Fever is relatively common in daily life, fever can cause dehydration and acid-base balance disorders, due to high fever and dehydration, eating antipyretics will sweat a lot, the body water loss, not only more difficult to reduce fever, and the blood sodium concentration rises, dry mouth, irritability, and even febrile convulsions, convulsions, which may lead to asphyxiation. 2. When the body temperature exceeds 41 degrees Celsius, the protein in the body will be decomposed, and there may be confusion, brain and nerve damage and so on. Therefore, if the body temperature is higher than or equal to 38.5 degrees Celsius, heat treatment should be immediately withdrawn.