’Amro bin Shu’aib narrated on the authority of his father, on the authority of his grandfather (RAA) that the Messenger of Allah (ﷺ) said:

“Anyone who practices medicine but is not known as a practitioner, and kills a human being or inflicts harm on him, will be held responsible.” Related by Ad-Daraqutni. Al-Hakim graded it as Sahih. Abu Dawud, an-Nasa'i and others also narrated it, but its Mursal form is stronger than the connected one.

وَعَنْ عَمْرِو بْنِ شُعَيْبٍ, عَنْ أَبِيهِ, عَنْ جَدِّهِ رَفَعَهُ قَالَ: { مَنْ تَطَبَّبَ ‏-وَلَمْ يَكُنْ بِالطِّبِّ مَعْرُوفًا‏- فَأَصَابَ نَفْسًا فَمَا دُونَهَا, فَهُوَ ضَامِنٌ } أَخْرَجَهُ اَلدَّارَقُطْنِيُّ, وَصَحَّحَهُ اَلْحَاكِمُ, وَهُوَ عِنْدَ أَبِي دَاوُدَ, وَالنَّسَائِيِّ وَغَيْرِهِمَا; إِلَّا أَنَّ مَنْ أَرْسَلَهُ أَقْوَى مِمَّنْ وَصَلَهُ.‏ [1]‏