Wilson: You're being cautious. You're being common. When you don't give a crap...

House: How many of your guys have caught cancer from their patients? Let me know when that happens, then we can have this conversation... I'll bet you can even have unprotected sex with your cancer patients without catching a damn thing. Boy I wish I had your job.

―Euphoria

Euphoria (Part 1) is a 2nd season episode of House which first aired on May 2, 2006, with the second part Euphoria (Part 2) airing the following night - the first and only double episode in the series. A police officer is admitted with symptoms of unbelievable happiness. However, his behavior starts changing as he gets sicker and sicker, when suddenly one of the team starts exhibiting inappropriate happiness as well.

Officer Joe Luria catches up to a criminal identified only as Babyshoes. However, after cornering Babyshoes in a dumpster, officer Luria starts acting very strangely, waving his gun around and laughing while attempting to read Babyshoes his Miranda Rights. Babyshoes takes the opportunity to shoot Luria, but the bullet shatters on Luria's bullet-proof vest, sending a shard into his skull, and subsequently earning him a trip to the ER. However, Luria's laughter persists.

As the doctors in the ER attempt to stop the bleeding, Luria's giddiness persists, causing House to take interest in the case. Foreman thinks it's just drugs, but the tox screen was clean. The bullet wound makes the team think trauma, but the symptoms started before the injury, which is in the wrong part of the brain to cause the symptoms in any event. The nature of the symptoms lead the team to consider carbon monoxide poisoning. Chase and Cameron are assigned to check the patient's blood gases and tend to the patient while House sets out to investigate Joe's police station. House sends Foreman to Luria's police car, personal car and apartment to see if he can find anything that would explain the symptoms.

Luria tests positive for carbon monoxide, so they plan to put him in a hyperbaric chamber and collect his medical history.

Despite his assurances to the contrary, Luria's living conditions turn out to be a cesspool, with uneaten food, trash, dirty plumbing facilities, rust, and general disarray. Foreman checks for a carbon monoxide leak, but finds nothing.

Luria starts losing motor function, another symptom that points to carbon monoxide poisoning.

Foreman finds a closed off shed on the roof. Inside is a hydroponic greenhouse Joe is using to grow large quantities of marijuana.

House's cursory investigation of the precinct reveals nothing, mainly because he is actually there trying to get several speeding tickets fixed on the pretext that he had a lot of emergencies. While Luria's partner deals with the tickets, House notices that Joe's desk is next to an air conditioner, that the stagnant water in it hasn't been cleaned out in some time, and one of the other officers is coughing.

Despite the marijuana found at Luria's apartment, House diagnoses Legionnaires' disease, the bacteria for which were growing in the cooled water in the AC unit. Foreman still thinks it is the marijuana, but House points out that Legionnaires' fits the symptoms better than marijuana use.

As Chase and Foreman check on the treatment, Luria starts feeling better. X-rays confirm that Luria had Legionnaires', but that the treatment has cured it. Luria is worried that Foreman is going to tell someone about the marijuana in his possession. Furthermore, Foreman realizes that Luria has gone blind even though he thinks he can still see.

Despite Luria's insistence that he's fine, the new symptom leads the team to believe there is damage to both occipital lobes of the brain. House thinks it must be a clot and orders a contrast MRI. However, an MRI is ruled out, due to the ferromagnetic bullet fragments still lodged in Luria's head. House thinks an angiogram won't work because the skull will interfere with the imaging, but the team insists on doing one anyway.

Foreman shows hostility towards the patient based on the fact that he's a hypocrite for arresting people for the same drug he uses. Cameron thinks Foreman should be off the case because of this, but House disagrees because Foreman is the team's neurologist. The angiogram shows nothing they can use, just as House expected. House still wants to do an MRI, so he finds a suitable corpse, produces a.38 caliber pistol, and shoots the corpse in the head to Chase and Cameron's surprise, but seemingly to Foreman's amusement.

As the team goes to test the MRI on the corpse, House begins to suspect that Foreman's recent behavior may be a sign that he has caught the patient's disease. However, Foreman says he is fine. They test the corpse with bullet fragments in the MRI, despite Cuddy's objections, and immediately destroy the MRI machine, which now can't be used for two weeks.

The team is at a loss as how to proceed, so House tells the team to check the heart to see if it's throwing off clots. While Chase is testing him, and finding no problems, Luria begins to bleed from his eyes and develops tachycardia and symptoms of shock. Foreman breaks out into laughter, earning odd looks from Chase and Cameron. Foreman notes that either thinning or clotting his blood will kill the patient, and wonders out loud why he's the only one who thinks the situation is funny.

Both Luria and Foreman are put into an isolation room. Foreman still claims he isn't ill. House plans to use the portable MRI on Foreman and tells him to take his own temperature. Chase and Cameron find House taking his own blood for testing, and orders them both to do the same. House notices on the MRI scan that Foreman's brain is softening, but he can't find a reason for it. Cameron volunteers to go to Luria's apartment again, but House tells her to just check the samples Foreman brought back.

Chase goes in to draw Foreman's blood. He tells him about the lesion on his cingulate cortex, which controls emotions. Foreman asks more questions and thinks it might be a staphylococcus infection despite his lack of fever. He suggests antibiotics.

Cameron and Chase's tests show nothing, but House refuses permission to go back to Luria's department. They can't biopsy Luria's brain because of the blood thinners, but House suggests they can biopsy Foreman's brain instead. However, the team objects due to the risk of brain damage.

House tells Foreman that he doesn't think it is staph because the brain wouldn't be the only organ affected. He asks Foreman to consent to a brain biopsy. Foreman asks to see his MRI. Foreman thinks it is an abscess, but House says if it was, he would have a fever. Foreman shows House he is running a temperature and asks for a shunt to deliver antibiotics directly to his brain.

Foreman is taken to surgery, but instead of inserting the shunt, House takes the opportunity to get a brain biopsy anyway.

Luria regains consciousness and finds Foreman in the room with him. Luria has gone totally blind, and now realizes it. However, Luria's condition starts to worsens to include extreme pain, as the infection is spreading into the pain center of his brain. Morphine isn't helping, and Luria is afraid he is going to die. Foreman tries to reassure him by telling Luria about the brain biopsy. Luria asks Foreman if he believes in prayer. Foreman says "not really" and Luria says he doesn't either. He then asks if Foreman wants to try praying. Foreman agrees.

The brain biopsy doesn't show any sign of staph. House sends Cameron back to the lab, but once again refuses to let her go back to the apartment. He also orders Cameron to run some tests on Foreman. Wilson confronts House, noting that with Foreman, he's being more cautious than usual. House responds angrily to Wilson by saying that cancer doctors never catch their patient's illnesses.

Luria's pain is getting worse, and he is at the maximum dose of morphine. Foreman is angry that House won't let Cameron go to Luria's apartment. Enraged, he deliberately stabs Cameron with a needle to expose her to whatever he has, essentially to motivate her to go back to Luria's apartment.

Chase and House discuss possible diagnoses with Foreman. Meanwhile, Cameron has donned an isolation suit and returned to Luria's apartment. Foreman discovers that not even a direct shot of morphine into Luria's carotid artery will stop the pain. The infection has spread into the pain center of the brain. House orders Chase to induce a coma in Luria.

House begins to figure out that Cameron's absence is due to the fact she's returned to Luria's apartment and goes to meet her there. House wonders why Cameron would risk her life for a guy who both stole an article and stabbed her with a needle. She says it was to save her own life, but House asks if that's the case why she bothered to wear an isolation suit. He wonders what Foreman would have to do to make her hate him. Cameron does get some other useful samples. House notices that there are three loaves of rye bread and sends Cameron back in because it's not consistent with Luria's habit of getting take-out to eat. The bread was used to feed pigeons, and Luria collected the droppings to fertilize his pot crop. It's a good chance that there is a parasite in the droppings, and Cameron takes a sample.

Foreman is worried - Luria's EEG may indicate his pain is getting worse despite the coma. Chase tells Foreman that Cameron hasn't shown any symptoms of the disease.

However, Luria's fever goes down, and his white blood cell count starts to improve. However, he then has a heart attack. Cameron runs in to say that they didn't find the parasite they were looking for. Foreman tries to resuscitate Luria, but fails. Luria dies from multiple system failure. House tells Foreman to note the time of death.

Legionellosis is not very common. Most people are naturally resistant to the disease and show only mild symptoms similar to a cold. The disease is much more severe in the elderly where it progresses in the same fashion as influenza.

• This is the second time that both Hugh Laurie and Scott Michael Campbell have appeared together. The two previously starred alongside each other in the 2004 movie, Flight of the Phoenix.
• Kyoto is a reference to the Kyoto Protocol, a treaty that has the goal of reducing the emission of greenhouse gases, primarily carbon dioxide.
• Foreman's patient file number is 8675-309, as seen on his MRI results, at about 19:30. This is a reference to a hit song from 1981 by Tommy Tutone.
• The precinct that Dr.House visits is the outside representation of the Brooklyn 99 precinct.
• This is the only episode of the series to end with a patient dying, and no diagnosis being successfully made as to what killed them. Other episodes have patients dying before House or his team can diagnose them, but with their cause of death being subsequently determined post-mortem by the end of the episode.

• In the beginning, when Babyshoes first goes to shoot Officer Luria it shows him reach for the gun with both hands but the slow motion shows him firing the gun with only one hand.
• Virtually all, if not all, modern hollowpoints of any caliber are non-ferrous. Foreman's "knowledge" which House finds so cool is very unrealistic. He would need to know what country the rounds were made in, how they were made, and a number of other miscellaneous facts about them to be able to make such a blanket statement as he did. Basically, though some rounds from other countries may have iron-based alloys in them, domestic rounds, which the perpetrator may have gotten hold of, probably wouldn't.
• After destroying the MRI machine, Chase incorrectly points out that the technicians will have to "shut down the magnet" to repair the damage. In other words: The magnet in an MRI machine is always on and therefore the bullet would have been pulled out of the corpse the moment it got in the room, it would not wait until the corpse is put inside the MRI and it will certainly not wait for the push of a button.
• The fact that Foreman knowingly and willingly stabbed a colleague with an infected needle would be legally be considered grounds for revoking a physician's licence. As this only happened because Chase left the needle in the room (especially following his earlier mistake). It's possible that Chase would have faced sanctions for his errors as well.
• In the scene where they do the Echocardiogram, they found that the heart was "healthy" and without clots, they were looking for the source of a possible brain embolism, and they suggest to check the legs for DVT. Unless the heart has a permeable oval foramen, there is no way an embolus can get to brain from the legs, they only get to the lung (producing a PE) and since they said that the heart was healthy (meaning no permeable foramen), they were just losing time, that or is an error in the script.
• As an immunologist, Cameron should have realized much sooner that House's diagnosis of cryptococcus neoformans was highly unlikely to be correct, as the parasite can only affect patients who are severely immunocompromised, usually as the result of either AIDS or immunosuppressants. Even if House was working under the assumption that the patient's immune system had been compromised by the legionellosis he had also been suffering from, there would be no reason for Foreman to have also contracted the disease, given that nothing in the episode indicates him to be immunocompromised.

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