Sahih al-Bukhari 2903
Narrated Sahl:
When the helmet of the Prophet (ﷺ) was smashed on his head and blood covered his face and one of his 
front teeth got broken, `Ali brought the water in his shield and Fatima the Prophet's daughter) washed 
him. But when she saw that the bleeding increased more by the water, she took a mat, burnt it, and 
placed the ashes on the wound of the Prophet (ﷺ) and so the blood stopped oozing out.
حَدَّثَنَا سَعِيدُ بْنُ عُفَيْرٍ، حَدَّثَنَا يَعْقُوبُ بْنُ عَبْدِ الرَّحْمَنِ، عَنْ أَبِي حَازِمٍ، عَنْ سَهْلٍ، قَالَ لَمَّا كُسِرَتْ بَيْضَةُ النَّبِيِّ صلى الله عليه وسلم عَلَى رَأْسِهِ وَأُدْمِيَ وَجْهُهُ، وَكُسِرَتْ رَبَاعِيَتُهُ، وَكَانَ عَلِيٌّ يَخْتَلِفُ بِالْمَاءِ فِي الْمِجَنِّ، وَكَانَتْ فَاطِمَةُ تَغْسِلُهُ، فَلَمَّا رَأَتِ الدَّمَ يَزِيدُ عَلَى الْمَاءِ كَثْرَةً عَمَدَتْ إِلَى حَصِيرٍ، فَأَحْرَقَتْهَا وَأَلْصَقَتْهَا عَلَى جُرْحِهِ، فَرَقَأَ الدَّمُ‏.‏