As a Moments subpage, all spoilers are unmarked as per policy. You Have Been Warned.
- The entire series premise in general where a person is suffering and or dying from something that cannot be explained or cured by a regular doctor so a certified genius has to be brought in who then goes through a series of wrong diagnoses before finally coming up with the right solution, sometimes at the very last minute!
- For extra effect, most of the root causes of the diseases they handle have innocuous origins. One woman nearly dies from an infection from a tick. An epidemic in the maternity ward severely afflicts six infants and kills one, originating from an elderly care worker who coughed on their teddy bears. A boy nearly dies from an infection acquired from the pitcher's mound where he practices baseball. A father and son end up with rare, exotic parasites from a fishing trip. So many nearly-fatal illnesses invoke Diabolus ex Nihilo, the show almost seems to be trying to induce germophobia.
- In the Season 1 episode "Paternity", House walks into a patient's room, casually ties him down and then amputates his toe with bolt cutters (it's just a hallucination).
- Season 1's "Maternity". The entire episode, really, but especially the newborn lying on the far too large autopsy table. Nightmare Fuel mixed with Adult Fear at its most unsettling.
- At the end of this episode we learn that an elderly hospital employee accidentally made the newborns sick (and killed one) by wiping her nose on her hand and then using that hand to give the babies stuffed animals. The discovery is made in the final moments of the episode and the consequences of a hospital employee killing the baby is never addressed.
- Season 1, Episode 7, "Fidelity". A woman suffering from a sleeping disorder that knocks her out for two thirds of the day seizes up, graphically aspirates (medical jargon for "pukes up stuff she didn't eat into a tube."). But the sheer horror comes when she complains of an itch on her arm. She claws at it, only for it to balloon up like a massive bubble, then erupt into swarms of black spiders. The fact that she's hallucinating the whole horrid thing does nothing to mitigate the nightmarishness of it all.
- Season 1's "Detox", especially the part where the withdrawal starts taking its toll on House, and he breaks his fingers with a pestle!
- "Babies and Bathwater" in season one forced a to choose between saving his wife and his unborn child. He chose his wife, but then complications ensued and she started to bleed to death with no way to save her. The husband then had to give the doctors permission to actively kill his wife by removing the baby or else both mother and baby would die - the only decision, really, but still incredibly difficult to have to go through with.
- House and Chase have both performed autopsies on babies.
- The Season 2 episode "Sleeping Dogs Lie" the patient of the week is completely unable to sleep despite being exhausted which leads her to down an entire bottle of sleeping pills. Worse yet, this still doesn't allow her to sleep, resulting in her partner finding her banging her head against the wall to the point where she starts bleeding, repeating that she "just wants to sleep". The insanely jerky camera movements during all of this really doesn't help either. Then it turns out she's infected by The Black Death.
- "Distractions" has an upsetting moment in which House prematurely wakes a burn victim. The poor kid first wakes up to excruciating pain, opens his eyes to find himself in a dark room (the lights had been turned off due to House's migraine), House demanding answers with the usual bedside manner, and finally notices the hideous burns on from his neck down. You have to applaud the kid for managing to tell House anything at all.
- Another particularly horrible example is found in the Season 2 two-parter "Euphoria" and the fate of the patient which as it turns out has spread to Foreman. Having a disease that constantly sets off all your pain receptors without as much as a finger prick has got to be one of the worst things imaginable, much less having it happen to the protagonist.
- At one point, the team puts the patient into an induced coma to keep the sheer agony from killing him. Monitoring his brain activity shows that he's still in pain.
- "Forever" from Season 2 has a father leaving his wife and new baby to go to work even though he is sick. At the door he decides he is too sick to go so returns upstairs, where he finds his wife having some sort of seizure in the tub. That's scary enough. Then he turns and sees his newborn baby in the bottom of the tub. To any parent that is more horrifying than drowning yourself. Towards the end of the episode, we see the mother smothering her own child.
- In "Who's Your Daddy?", the penultimate episode of Season 2, House has to prove to his team that the patient's hallucinations are pain induced. He pricks her with a needle, and when that doesn't give results, he breaks her finger. Cue a point-of-view shot from the patient's eyes and the audience getting to see Hugh Laurie's face melt. Lovely.
- House throws in some more-or-less Real Life Squickfest whenever possible. The Season 2 finale "No Reason" features a man whose body organs swell up and sometimes explode, including his tongue, testicles and an eyeball. It all turns out to be an hallucination on House's part.
- Perhaps the worst moment comes at the end, when House takes control of the robot surgeon and slices the man open from stomach to chest with the intent of killing him so the hallucination will end. This takes just long enough to make you wonder if maybe he was wrong about everything being a hallucination, and he might have just actually killed a man. Alternately, of course, House might have been putting the man out of his misery. In a very, very, VERY loose sense of the word.
- The REAL Nightmare Fuel aspect of that episode is how House is hallucinating all through the episode and neither he, nor the viewers, know exactly what is and isn't real.
- The hallucinations that the boy has in "Cane and Able".
- In "Que Será Será", where a man is having a hole drilled through his skull so that his brain can be directly injected with something that is believed to be a cure for his unexplained coma. Not long after the needle's stuck through his brain, he completely loses his vision. Which, understandably, causes him to panic. And then try to break out from the chair, completely disregarding the fact that his skull's wide open and there's a needle stuck through his brain. It's later found out that he didn't go blind from a needle punching through the wrong parts of his brain, it was actually an unfortunate effect of terminal lung cancer - which had also caused his coma.
- The head drilling and needle-sticking-in are themselves quite disturbing to look at. Especially the needle-sticking-in - holy hell, the scraping sounds that it makes are so wrenching...
- Season 3 episode: the rats in "Informed Consent" a researcher has a medical episode and his rats start chewing on him. Anyone who's had pets and been afraid of dying in the same way will shudder.
- In Season 3's "Insensitive", a girl who was physically incapable of feeling pain was brought into surgery without anesthesia. House cuts her stomach open while she's watching, producing a 25-ft tapeworm that he proceeds to extract before her eyes.
- Another Season 3 example, "Family". The scenario: two young black brothers are willing to risk their own lives to cure the other. One needs bone marrow for the entire episode, but the other brother gets an infection that jeopardizes any chance of a bone marrow infusion. Eventually, the donor brother gets cured of his infection, but Foreman convinced him to do an emergency bone marrow extraction without anesthetic to save his brother. Forcefully and swiftly. The screaming of that kid never leaves your head, and that was after filling only two syringes with bone marrow: Foreman implies that he needs a lot more. Shudder. Between torturing the kid to cure his brother and accidentally killing a patient the previous episode, no wonder Foreman wanted to get away from House and his Despair Event Horizon-inducing practices.
- The Season 3 episode, "Resignation". The patient's in the MRI, and she starts complaining that her head hurts. Her scalp is split open. Her illness caused her stomach acid to flow through her vascular system, collect at the top of her skull AND BURN THROUGH! Foreman later mentions it looks like "massive tissue death".
- The season 4 episode "Guardian Angels", involving a woman who worked in a funeral home who kept having hallucinations. As well as seeing her dead mother, House's grandfather and the patient Thirteen accidentally killed last episode, there was a very creepy scene where Kutner stabbed the patient's arm with a hypodermic while Thirteen held her down, and then Kutner pinned her down and Thirteen stabbed the needle into her arm, both of them looking at each other with really creepy smiles and then smiling at all the blood. Then the patient wakes up, covered in sweat, to see Thirteen leaning over her, trying to reassure her that she's OK and it was a nightmare. The patient says that her arm is bleeding; Thirteen thinks it's just a part of the nightmare... until she looks at the patient's arm... and there are the stab wounds, plus the blood.
- Waking up Amber in "Wilson's Heart". Wilson seemed horrified at the idea, but everyone seemed to think it was perfectly okay to wake up a dying woman just to tell her she was dying and have a bunch of people she didn't even like say their goodbyes.
- The detox scenes. Jesus Christ. Amber taunting House makes it creepier.
- Remember "Not Cancer", the Season 5 episode with the four dead transplant patients from five years ago, where the fifth hallucinated, without segue or warning, that House (otherwise perfectly in character) was performing an impromptu cephalectomy with a meat cleaver? Watch one of your favorite characters, one who occasionally carries out seemingly irrational medical procedures, attempt to remove a patient's head without batting an eye. To say nothing of the death montage at the beginning of the episode, where the other transplant recipients all drop dead for no obvious reason.
- In the Season 5 episode "Joy", Taub tells a patient: "I think... you're sweating blood." Made all the more awful because even Taub sounds utterly creeped out.
- Not only that, the patient and his daughter's sheer emotionless, robotic manner. It's horrifying. Thank God they get better.
- Season 5's The Greater Good. The patient ends up itching through her skull to the point of leaking brain matter, and the very first thing that she says after the wound is closed? It still itches.
- Episode 19, Season 5, appropriately titled "Locked In", in which a patient is locked inside his own body, unable to move, communicate, or even do much to indicate he's alive, but remains fully aware. He's almost autopsied before the episode even gets underway. Try not to think about that too much.
- None of these hold a candle to the Season 5 endgame starting from the moment Kutner kills himself. The penultimate episode of the season turned House's increase in mental instability up to eleven. Enjoy yourself, it's later than you think...
- If you look closely at the scene where Foreman and Thirteen find Kutner's body, when Foreman pushes her to the side, Thirteen slips in his blood.
- Absolutely anything featuring the hallucination of Amber's ghost. Especially the terrifying ghostly rendition of Enjoy Yourself.
- From a more emotional standpoint, there's something so very wrong about House having to stay in a mental institution. That last shot of him looking terrified is creepy.
- They managed to make a Vicodin bottle scary, as when House realizes he's been hallucinating, and it switches from scenes of him playing with a lipstick to what he's actually doing: playing with a pill bottle while everyone stares at him, disturbed.
- The worst moment comes when he fully realizes just how bad the hallucinations have gotten. Seeing Amber's ghost was creepy enough. But Kutner's ghost makes it much, much more terrifying; House's mind is gone, and all that's left is a vision of death.House's face is in frame, slightly to the right. Then Amber's ghost comes onscreen from the left, right next to his face.
Amber: (Whispering) So. This is the story you made up about who you are. It's a nice one.
The camera switches to a view of Kutner's ghost who is standing in the room, and slowly zooms in.
Kutner: (Somberly) Too bad it isn't true.
The camera briefly goes back to Amber's ghost, who gives House a little smile. Then it goes back to Kutner's ghost, who gives House a cold, unblinking stare. It's at this moment when House finally breaks.
- The psychopath in Season 6's "Remorse". That creepy glance she shot at Thirteen was priceless.
- It's chilling when House first confronts her, she realizes he's on to her, and she drops the fake facade. The subtle, yet unnerving change in her eyes and voice...
- Season 6 "Black Hole". The visions the patient has of falling into a black hole.
- Greatly reduced horror in the next scene when the following exchange takes place:Foreman's face is in frame. Switch frame to the patient.
The patient: It's a black hole.
Foreman: She's hallucinating.
Taub: I certainly hope so.
- Greatly reduced horror in the next scene when the following exchange takes place:
- Season 7's "Massage Therapy" features a schizophrenia-induced hallucination that looks to be straight out of a horror movie, with all sorts of Body Horror. House finally convinces the patient that she's hallucinating by calmly placing his hand on a table that she informs him is on fire, which it naturally appears to be to the audience until House dispels the illusion.
- House's Breaking Speech to Masters in "Family Practice". She literally has to go puke afterwards.
- When House jumps off the balcony and into the swimming pool in "Out of the Chute" (Season 7) it appears to viewers and the onlooking Wilson that he's going to commit suicide. His behavior is so manic and impenetrable that it might really have been one of his options in the wake of his breakup with Cuddy.
- The last few seconds of "Fall From Grace". It turns out that the team saved a cannibalistic serial killer - and let him escape...
- In Season 7's "The Last Temptation", the patient, who postpones a surgery in order to complete a month-long sailing race, is drugged into a cardiac event. She later wakes up without her arm.
- Season 7's "After Hours". House performing surgery on his own leg with the intent on cutting out tumors was bad enough, but then his hand had to start shaking and the scalpel slipped and the blood and the shaky cam... It might just be the most nightmarish sequence in the series. You can't help but feel House's growing panic as the pain gets too unbearable for him to continue.
- Wilson's chemo in "The C Word". The sweating, shaking, vomiting, hallucinations, him almost going insane...