Mukhtasar Bukhari

Narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) said: "If a fly falls into the food of any one of you, then dip it (once) and throw it away, for in one of its wings there is healing and in the other there is disease (so when it enters something, it dips the wing with disease)."