The reduction or alleviation of a fever; in medicine it can refer to measures or drugs that lower body temperature.
熱が下がり、解熱したので仕事に戻った。
My fever went down, so I returned to work.
解熱剤を飲んでも熱が下がらない場合は医師に相談してください。
If your fever doesn't go down after taking antipyretics, consult a doctor.
患者は解熱後もしばらく安静が必要だ。
The patient needs to rest for a while even after the fever subsides.