It is not lawful to ascribe every disease that one may have to the actions of the jinn or black magic.
If a person feels something wrong with himself, he should go to a doctor. The Prophet (peace and blessings be upon him) said: “O Allah’s servants, seek treatment.”
Going to a doctor does not contradict with reading ruqyahs (protective statements taught by the Prophet—peace and blessings be upon him) as a means of treatment.
What is important is to believe that healing is by Almighty Allah’s Will and that seeking treatment by taking medicines or reading ruqyahs cannot have any effect unless Allah Almighty wills so.
Muslims should beware of charlatans and sorcerers who exploit the sick by claiming that they can treat their illness with the Qur’an. Getting close to Allah Almighty, obeying Him, and reading the Qur’an frequently are the shields that can protect one against falling prey to the charlatans and the jinn.

Dr. Husam ad-Din ibnMusa `Afana, professor of the Principles of Jurisprudence at the University of Al-Quds, Palestine, states the following: There are many people nowadays who claim that they can use the jinn in treating the sick. Those people are, mostly, charlatans and sorcerers. They exploit the ignorance and need of those who seek their help so as to take money from them unfairly. This is against the Shari`ah. There are many points that should be clarified on this subject.
First, if a person feels something wrong with himself, he should consult a doctor about that. Allah Almighty has created for every disease the treatment that can cure it.
the Prophet (peace and blessings be upon him) said, “There is no disease that Allah Almighty has created, except that He also has created its treatment.” (Reported by Al-Bukhari)
he (peace and blessings be upon him) also
said, “There is a remedy for every malady, and when the remedy is applied to the disease it is cured with the permission of Almighty Allah.” (Reported by Al-Bukhari and Muslim)
Second, seeking treatment by reciting the Qur’an and ruqyhas is lawful. Allah Almighty says: (And We reveal of the Qur’an that which is a healing and a mercy for believers though it increase the evil doers in naught save ruin. ) (Al-`Israa’ 17:82)
according to Al-Bukhari, Abu Sa`id Al-Khudri (may Allah be pleased with him) reported: Some of the companions of the Prophet came across a tribe amongst the tribes of the Arabs, and that tribe did not entertain them. While they were in that state, the chief of that tribe was bitten by a snake (or stung by a scorpion). They said, (to the companions of the Prophet), “Have you got any medicine with you or anybody who can treat with ruqyah?” The Prophet’s companions said, “You refuse to entertain us, so we will not treat (your chief) unless you pay for it.” So they agreed to pay them a flock of sheep. One of them (the Prophet’s companions) started reciting Surat Al-Fatihah and gathering his saliva and spitting it (at the snake-bite). The patient was cured and his people presented the sheep to them, but they said, “We will not take it unless we ask the Prophet (whether it is lawful or not).” When they asked the Prophet (peace and blessings be upon him) about that, he (peace and blessings be upon him) smiled and said, “How do you know that Surat Al-Fatihah is a ruqyah? Take it (flock of sheep) and assign a share for me.”
according to an authentic hadithreported by Muslim, `A’ishah (may Allah be pleased with her) said: “When a member of the Prophet’s family got ill, he (peace and blessings be upon him) would blow over his body by reciting Al-Mu’awwidhatayn (the two protective surahs, Al-Falaq and An-Nas) and would rub him with his hand.”
Third, no one should claim that he dedicates himself to curing others of barrenness and incurable diseases, dispelling the spells of black magic, ridding others of the possession of jinn and evil eyes by reciting the Qur’an, ruqyahs and dhikr.
no one of the Prophet’s companions or the righteous successors was ever reported as having done something of such a kind, although people in their time suffered also from the same or similar diseases and afflictions.
Besides, doing something of such a kind may open the door to many evils and give the chance to charlatans and sorcerers to do acts of corruption.
Fourth, there is nothing wrong in reciting some verses of the Qur’an over a vessel of water so that a patient can drink and wash his body from the water.
Ibn Al-Qayyim said, “A group of the righteous predecessors were of the opinion that some verses of the Qur’an could be written and put in a vessel of water for a patient to drink from. Mujahid said, ‘There is nothing wrong in writing some verses of the Qur’an and putting them in a vessel of water so that a patient can drink and wash his body from it.’ A similar point of view was also reported to have been adopted by IbnQilaba.”
Fifth, it is true that the jinn can possess a human being and dwell in his body. This is proved by Almighty Allah’s Book and His Prophet’s Sunnah, and it is seen also in people’s lives.
Imam IbnTaymiyah said, “There is no Muslim imam who denies that the jinn can dwell in the humans’ bodies. He who denies that and
claims that it is against the Shari`ah is distorting the Shari`ah itself. There is nothing in the Shari`ah against the jinn’s ability to possess human beings.”
Curing a human being of the harm of the jinn is to be achieved through reciting the Qur’an and the protective statements reported to have been said by the Prophet (peace and blessings be upon him) in that regard.
Sixth, it is not lawful for one to resort to a person who claims the ability to cure others by the Qur’an or rid them of jinn possession unless one makes sure that that person is righteous and sticks to the teachings of Almighty Allah’s Book and His Prophet’s Sunnah, and that that person follows the lawful ways in treatment through ruqyahs and does not use the jinn in that respect, for the jinn would never serve a human being unless that human deviates from the right path.
Besides, some of those who claim the ability to cure others through the Qur’an use non-understandable words in that respect, and this is also unlawful.