Why does body temperature drop and then rebound during a fever?

Fever refers to an elevated body temperature. A fever that goes down and then rebounds may be caused by medication factors, unresolved underlying causes, improper care, or other reasons.

1. Medication factors

Antipyretic medications can lower body temperature after fever onset, but several hours later, as the drug's effect wears off, the temperature may rise again, leading to a rebound in fever. It is recommended to switch antipyretic medications under a doctor’s guidance.

2. Unresolved underlying cause

If fever is caused by inflammatory stimulation, the fever symptoms can only be effectively controlled once the inflammation has completely subsided. If inflammation persists, it may lead to recurring fever—temperature drops followed by rebound. It is recommended to treat the fever based on the underlying disease under medical supervision. For bacterial infections, medications such as amoxicillin capsules or cefaclor capsules may be taken as prescribed. For viral infections, medications such as ribavirin granules or oseltamivir phosphate granules may be used according to medical advice.

3. Improper care

Failure to maintain adequate warmth during fever may allow cold air to invade the body again, potentially causing recurrent fever and temperature rebound. It is recommended to rest adequately, avoid excessive fatigue, and pay attention to staying warm.