" مَنْ تَطَبَّبَ وَلَمْ يُعْلَمْ مِنْهُ طِبٌّ قَبْلَ ذَلِكَ فَهُوَ ضَامِنٌ "
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)