After the fever symptoms appear after breast malignant tumor infusion of Thymopeptide, it is possible that they will slowly disappear after a day or so. Thymopeptide is a kind of small molecule peptide drug, some patients with breast malignant tumors after infusion of this drug, due to the change of the body’s immune function, may produce fever symptoms, usually lasts for about 1 day, then the body temperature will gradually drop, the body will gradually adapt to the drug, and dizziness, fatigue and drowsiness and other abnormal symptoms will be reduced slowly. If patients with breast malignant tumors develop fever after infusion of thymopeptide, they need to actively monitor the changes in body temperature, and if necessary, they can also use a cool towel to wipe their foreheads, armpits and other parts of the body to physically cool down the temperature, and if there is no significant improvement or if the symptoms continue to worsen, it would be best to consult a doctor for examination in a timely manner.