Abu Dawud narrates through his isnad that the Prophet said, “He who practices medicine but is not known for medicine, is liable.”
(مَنْ تَطَبَّبَ، وَلَا يُعْلَمُ مِنْهُ طِبٌّ، فَهُوَ ضَامِنٌ)

This hadith outlines for us to broad legal concepts in Islamic law: negligence and willful misconduct.

Here the inverse of the Prophet’s statement “but is not known for medicine” refers to the person qualified to practice medicine. When a person is qualified to practice a profession or offer advice in an area of expertise, they are expected to maintain decorum and adhere to the professional principles and ethical behavior specific to that profession. When they neglect standards and fail to exercise what a reasonably prudent person would take into consideration while practicing their profession, they are liable for the harm and damages they cause. The inverse of this hadith would seem to indicate that the professionally qualified person is not liable, in lieu of his qualifications. This however is not the case, as the inverse of this statement agrees with the ruling in the hadith when specified by two other evidences: other texts such as “No harm or reciprocating harm,” etc. and consensus that anyone practicing medicine who engages in misconduct and/or negligent behavior is liable.

When a person offers professional advice or practices a profession he is unqualified for, the ruling mentioned expressly in this hadith applies. This person will be liable for damages and harm resulting from their misconduct and misrepresentation, however will not be held fully responsible for death and bodily harm because they would not have been able to practice without some sort of permission from the person harmed.

This hadith is an important reminder to people who profess facts to others, spin conspiracy theories based on conjecture, and make baseless claims about issues which they are wholly unqualified to pass judgment on. Even worse is when this translates into practicing “Prophetic Medicine” without having the foggiest what that means, or warning against all forms of vaccinations, or generally promoting ideas that are harmful to our health.

Let’s remember to be responsible in all that we do and say.