In The Exorcist, why does the demon that possesses Regan react to the “fake” holy water sprinkled by Father Karras?

It’s hard to believe that the demon mistakes the tap water for water blessed by a priest. It certainly makes the entity that much less frightening.

  • 4
    I think the demon was fooling around with the father.
    – Mistu4u
    May 3, 2013 at 6:57
  • 1
    Great question. That part always confused me. None of the explanations in these posts help. Did the novel explain it better? I never read it.
    – user8856
    Mar 30, 2014 at 2:56
  • 1
    It raises the question - is it a demon, messing with the father, is it a child in the throes of a non-magical episode where she is acting out what she believes to be a demonic possession? It's supposed to make you wonder. Aug 31, 2016 at 19:21

4 Answers 4


It may be the case that the demon is cunning and wanted to make a doubt in the mind of Karras, already having a lack of faith in demons and ghosts. As we have seen that demon plays with Karras' emotions related to his mother too.

The demon reads on mind and emotions so it's not possible that he got fooled by tap water at all.

  • I agree with that assessment, but Holy Water is a myth in itself, as water is a good conductor of energy, the act of passing positive energy onto a negative body is more the association it would hold, so by the simple act of touching the water a person of "light" would make it a weapon, the blessings Catholicism make on water to make it "Holy" are just like a mantra that focuses the state of the "Blesser" to that "light" condition.
    – Raytrek
    Mar 30, 2014 at 10:20
  • 2
    @Raytrek I do not believe it is a good idea to make a myth out of the Holy Water. I do not mean to make assessments on all beliefs here, but the Orthodox Church(and I am almost sure it also applies to the Catholic Church - they are very similar) considers that the water is made holy by the action of the Holy Spirit, called by the priest's prayers. So it is not the energy of the priest, it is the doing of God(the Holy Spirit). So, because the film seems to be taking religious beliefs seriously, your comment seems to be inadequate in this case. It is a point of view, but not applicable here.
    – Dragos
    Mar 31, 2014 at 11:54
  • Some people believe the Holy Spirit is a distinct individual, others consider it an active force that moves those touched by it to the work of God. It is really just semantics.
    – Raytrek
    Mar 31, 2014 at 17:26
  • 1
    @Raytrek, I believe Dragos was commenting on this statement of yours "...but Holy Water is a myth in itself"
    – bobbyalex
    Apr 2, 2014 at 2:12
  • 1
    A Holy Man, like Father Karras, however could feasibly be an actual container of Holy Spirit, and even in a case where he had no faith in the Holiness of the water, his faith still existed in God, and despite the water being mere tap water, it was still capable of conducting his faith and therefore weaponising the water. This is just a theory I am suggesting, as I said I like the previous answer of the Demon tricking Father Karras in order to undermine his faith.
    – Raytrek
    Apr 2, 2014 at 23:00

Father Merrin answers this question for us when he arrives at Regan's house and speaks to Father Karras prior to starting the exorcism. He says to Father Karras, "He's a liar. The demon is a liar. He will lie to confuse us, but he will also mix lies with the truth to attack us."

So whoever it was that pointed out the fact the demon was probably faking it when he comes in contact with the fake holy water in order to confuse Father Karras and cause doubt to avoid exorcism was also correct.


According to Damien Karras, the demon's reaction to the tap water could mean that the possession is not genuine. This would therefore weaken his case for an exorcism. So, it could be that the demon was deliberately reacting to the tap water so Karras would not get permission to perform the exorcism.

  • So if this is true, why after the "fake" reaction to the holy water didn't Karras tell the demon it was only tap water to let the demon know he was onto him? Basically play the demon at his own game of deception. Once the demon knew he had been caught, then perhaps he would be less likely to try again or maybe know he could more easily get caught in a lie.
    – David
    Apr 16, 2020 at 17:59
  • At the time of the holy water test, Karras didn't want to believe that Reagan was possessed so he doesn't follow up; he's losing his faith and recommends that she receive professional psychiatric care instead of entertaining what he considers to be a delusion (he is a psychiatrist, after all!).
    – Herr Pink
    Oct 19, 2021 at 12:48

The reasoning for this scene is to sprinkle a little truths and lies into the mix. The demon both told the truth (told Damien an Exorcist will bring them together cause it LITERALLY does at the end) and lied (Damien spoke Latin to the demon and it didn't exactly reply in Latin as soon as Damien pressed the recorder; Regan starts speaking French so he'd have no proof) ergo the demon wanted DAMIEN and Damien ALONE to do the exorcism, that's why the fake holy water scene exists so Damien can go back and tell for the priests to think she's faking, he'll feel bad about being rejected, do the exorcism anyway but cause he's not strong enough he'll tell the demon to go into him (basically the ending) except before this happens, he brings the other priest so the demon killed it so it can have Damien alone and so forth

  • 1
    Hi Doodle, welcome to M&TV. Can you improve the phrasing of your answer? It's basically one run-on sentence. And please also go through the existing answers, as I believe there is a lot of overlapping information here. Please take the Tour to get to know how this platform works.
    – Joachim
    Sep 10, 2023 at 8:59

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .