Whoever practises medicine without being known for medical knowledge is liable

Amr bin Shu'ayb narrates from his father, from his grandfather (Sayyiduna Abdullah bin Amr bin al-As, may Allah be pleased with them both), that the Messenger of Allah (peace and blessings be upon him) said: "Whoever practises medicine without being known for skill in medicine, he is liable (for any harm to life or property)."
This hadith has a sahih (authentic) chain, but the two Shaykhs (Bukhari and Muslim) did not record it.

It is narrated from Sayyiduna Awf bin Malik al-Ashja'i (may Allah be pleased with him) that he said: We used to perform ruqyah (incantations) in the days of ignorance (Jahiliyyah), so we said: "O Messenger of Allah, what is your view on that?" He (peace and blessings be upon him) said: "Present your ruqyahs to me. There is no harm in ruqyah as long as it does not contain (any trace of) shirk."
This hadith has a sahih (authentic) chain, but the two Shaykhs (Bukhari and Muslim) did not record it.

It is narrated from Sayyidah Umm Salamah (may Allah be pleased with her) that the Prophet (peace and blessings be upon him) saw a girl in her house who had a yellowish or dark discoloration (saf'ah) on her face, so he (peace and blessings be upon him) said: "Have ruqyah done for her, for she has been afflicted by the evil eye."
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it.