The Prophet ﷺ said "If a house fly falls in the drink of anyone of you, he should dip it (in the drink) and take it out, for one of its wings has a disease and the other has the cure for the disease."
سَمِعْتُ أَبَا هُرَيْرَةَ ؓ يَقُولُ قَالَ النَّبِيُّ ﷺ إِذَا وَقَعَ الذُّبَابُ فِي شَرَابِ أَحَدِكُمْ فَلْيَغْمِسْهُ ثُمَّ لِيَنْزِعْهُ فَإِنَّ فِي إِحْدَى جَنَاحَيْهِ دَاءً وَالأُخْرَى شِفَاءً