12 – Abū Hurayrah (may Allah be pleased with him) reported that the Messenger of Allah ﷺ said: “If a fly falls into the drink of any one of you, let him plunge it completely, then remove it, for one of its two wings carries disease and the other carries the cure.” The ḥadith was recorded by al-Bukhārī and Abū Dāwūd, who added: “The fly protects itself with the wing that holds the disease.” (1)

Hadith grading
The additional wording reported by Abū Dāwūd has a sound chain of transmission.

Glossary of terms
• Fly (dhubāb): a name applied to many winged insects, including the common housefly with its transparent wings and hair-covered legs that end in suction pads, enabling it to carry germs and filth. Ibn Baṭṭāl said it is called dhubāb because whenever it is driven away (dhubba) for being repulsive, it returns.
• Drink (sharāb): any liquid that is drunk; plural ashribah.
• Let him submerge it (fal-yagmis-hu): into the drink, then take it out; “inghamsa in water” means to be completely immersed.
• Then let him remove it (thumma liyanziʿ-hu): let him pull it out of the drinking vessel.
• Its two wings (janāḥay-hi): a wing is what a bird or similar creature flies with; plural ajniḥah or ajanuh.
• Disease (dāʾ): an illness, outward or inward; plural adwāʾ. Here it refers to the cause of disease found in one of the fly’s wings.
• Cure (shifāʾ): recovery from illness; here it refers to the cause of healing found in the fly’s other wing.