Fever can cause fainting. First of all, if a patient with fever has a high body temperature, it can cause damage to the central nervous system, and fainting can occur. Secondly, a feverish patient with reduced appetite can develop anemia, which can also lead to fainting. Lastly, patients with fever may faint due to excessive sweating and loss of body fluids, in which case they may also faint. Therefore, patients with fever are advised to drink more water, rest more, increase nutrition, and maintain indoor and outdoor air circulation, only in this way can we prevent the occurrence of complications.