Sunan an-Nasa'i, Volume 5, Book 45, Hadith 4834 (DarusSalam) ⓘ
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 " .
also referenced under: Hadith 4830 (Reference) & Book 45, Hadith 125 (In-Book)