Jinns’ contact with humans

Yes, it is proven that the jinn can possess
humans and harm them. Allaah says concerning those who deal in riba
(interpretation of the meaning): 

“Those who eat Riba will not stand (on
the Day of Resurrection) except like the standing of a person beaten by
Shaytaan (Satan) leading him to insanity”

[al-Baqarah 2:275]

i.e., when they rise from their graves at
the Resurrection, they will only stand like one who has been possessed by
the jinn because the belly of the one who deals in riba – Allaah forbid –
will be huge, so when he wants to stand up he will fall down, and every time
he wants to stand up he will fall down and be exposed before all people, so
he is likened to the possessed man who has been overcome by the jinn and
devils. This indicates that the jinn can possess humans, which is something
that is proven and well known from visible experience. The jinn can enter
humans and possess them, causing them to go insane, either because the human
has harmed them and they want to take revenge on him, or because they are
toying with him, or for some other purpose that they are seeking. 

To sum up: it is proven that the jinn can
harm humans by possessing them, and this is indicated by the Qur’aan and by
visible experience that no one can deny but one who is ignorant. 

The best means of dealing with that is
reciting Qur’aan over the one who is affected, and treating him with ruqyah
that contains du’aa’s narrated from the Prophet (peace and blessings of
Allaah be upon him), and what he is suffering will disappear, in sha
Allaah. 

As for what some charlatans and liars do
nowadays, such as prescribing some du’aa’s and drinks, claiming that this
will bring the jinni out of the body of the person, the basic principle is
that this is haraam and it is not permissible to treat such cases except
with du’aa’s from Qur’aan and Sunnah. End quote.