Whenever a lady suffering from fever was brought to Asma' bint Abu Bakr, she used to invoke Allah for her and then sprinkle some water on her body, at the chest and say, "Messenger of Allah ﷺ used to order us to abate fever with water." (Using translation from Bukhārī 5724)   

أَنَّ أَسْمَاءَ بِنْتَ أَبِي بَكْرٍ كَانَتْ إِذَا أُتِيَتْ بِالْمَرْأَةِ قَدْ حُمَّتْ أَخَذَتْ الْمَاءَ فَنَضَحَتْ بَيْنَهَا وَبَيْنَ جَيْبِهَا وَقَالَتْ إِنَّ رَسُولَ اللهِ ﷺ كَانَ يَأْمُرُنَا أَنْ نُبْرِدَهَا بِالْمَاءِ