Narrated Abu Hazim:

The people asked Sahl bin Sa`d As-Sa' idi "With what thing (medicine) was the wound of Allah's Messenger (ﷺ) treated?" He replied, "There is none left (living) amongst the people who knows it better than. `Ali used to bring water in his shield and Fatima (i.e. the Prophet's daughter) used to wash the blood off his face. Then a mat (of palm leaves) was burnt and its ash was inserted in the wound of Allah's Messenger (ﷺ) ."

حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا أَبُو حَازِمٍ، قَالَ سَأَلُوا سَهْلَ بْنَ سَعْدٍ السَّاعِدِيَّ ـ رضى الله عنه ـ بِأَىِّ شَىْءٍ دُووِيَ جُرْحُ النَّبِيِّ صلى الله عليه وسلم فَقَالَ مَا بَقِيَ مِنَ النَّاسِ أَحَدٌ أَعْلَمُ بِهِ مِنِّي، كَانَ عَلِيٌّ يَجِيءُ بِالْمَاءِ فِي تُرْسِهِ، وَكَانَتْ ـ يَعْنِي فَاطِمَةَ ـ تَغْسِلُ الدَّمَ عَنْ وَجْهِهِ، وَأُخِذَ حَصِيرٌ فَأُحْرِقَ، ثُمَّ حُشِيَ بِهِ جُرْحُ رَسُولِ اللَّهِ صلى الله عليه وسلم‏.‏