Narrated by:from'Amrbin shu'aib
It was narrated from'Amrbin shu'aib, from his father that his grandfather said:"the Messenger of Allah said: 'Whoever practices medicine when he is not known for that, he is liable.(Daif)
أَخْبَرَنِي عَمْرُو بْنُ عُثْمَانَ، وَمُحَمَّدُ بْنُ مُصَفًّى، قَالاَ حَدَّثَنَا الْوَلِيدُ، عَنِ ابْنِ جُرَيْجٍ، عَنْ عَمْرِو بْنِ شُعَيْبٍ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ تَطَبَّبَ وَلَمْ يُعْلَمْ مِنْهُ طِبٌّ قَبْلَ ذَلِكَ فَهُوَ ضَامِنٌ " .
Nesai
The Book of Oaths (qasamah), Retaliation and Blood Money • Hadith 4830