Continuity mistake: Chase is 26 years old in season one. In season two he's 30.
Plot hole: When Wilson does an ultrasound to check for cancer in Alex' ovaries he fails to notice the fact that she doesn't have a uterus. If he mistook her bladder for her uterus, which sometimes happens, she would have appeared to be missing her bladder instead. Yet Wilson doesn't pick up on anything being missing.
Failure to Communicate - S2-E10
Continuity mistake: When the scene starts with Stacy and House in the airport about to start talking, she has a pen in her mouth. In the very next shot it's on her ear, and in the next it's gone. It switches back and forth throughout the rest of the scene.
Continuity mistake: In Season 2, Episode 17 - "All In", the young patient goes into respiratory arrest. You see the doctors remove the pillow from underneath his head to put the breathing tube in, but in the next shot, the pillow is back.
Factual error: When Andie is going in for her MRI, Chase starts the machine with Andie's steel IV pole in the room. No doctor would ever do that considering the damage that would be done to machine and patient. (00:05:45)
Plot hole: In the scene with Mikey in the NICU, the alarms start to go off, stating that he is in distress. The nurse screams "He's in V-fib!" and everyone rushes around him. In the next shot they show the heart monitor just before Chase shocks Mikey's heart. The problem is that the heart rate is so fast with one wide complex that it would actually be Supraventricular Tachycardia with 1 Premature Ventricular Contraction (SVT with 1 PVC), which is far less serious than V-fib and wouldn't require the heart to be shocked.
Continuity mistake: About 5 minutes in, when Foreman struggles with opening the coffee package, House rips the entire top of the package off with his teeth. In the following shots, you can see that the coffee package merely has a corner ripped off.
Factual error: The patient is diagnosed with legionnaire's disease, caught from the AC unit above their desk. The legionella bacteria causing the disease is found in warm water (commonly dehumidifiers, industrial AC cooling towers, hot water tanks) - the key point being that a water source is required. The problem with this is that the AC unit above the patient's desk is a window unit. These sorts of AC units don't use water as a coolant - you can't catch legionnaire's from them.
Factual error: Naegleriasis is a rare disease, and all the known cases involved people who had submerged their nostrils in contaminated water (commonly while swimming or diving). Foreman's exposure was just that he walked past a mister spraying contaminated water: nowhere near enough exposure to get infected. It's also highly unlikely Foreman would have survived Naegleriasis (which has an extremely high death rate) and without lasting brain damage - particularly given the length of time before diagnosis.
Factual error: Cameron forces House (against his wishes) to do the biopsy on Foreman because Foreman has made her his medical proxy. This is completely incorrect; Cameron may be Foreman's proxy, but that doesn't mean she can overrule the attending doctor. Having the right of medical proxy allows her to *refuse* a test in Foreman's name (or refuse consent to any number of medical activities on Foreman), but absolutely not to order a test or operation contrary to the attending doctor's views. (00:34:45)
Character mistake: When discussing plasmapheresis, Foreman incorrectly classifies white cells as the heaviest (most dense). The correct order is red cells white cells, platelets, plasma. (00:25:06)
Continuity mistake: Ian (the patient) moves his hand while he is in cardiac arrest, then almost immediately, Chase checks Ian's pulse and the sleeve of his shirt changes position. (00:31:10)
Character mistake: House says to Chase "I've got a dead baby for you to biopsy." A biopsy is a test performed on tissue from a living patient. He should have said 'autopsy' - the procedure performed on a dead person to determine how they died. House, as a doctor, would know this distinction. (00:32:45)
Acceptance - S2-E1
Continuity mistake: House crosses out 3 of 5 stages around the 30-minute mark. Later in the episode, those stages aren't crossed out. (00:30:00 - 00:40:20)
Continuity mistake: When the wife is taken away by the police, it's late in the evening: the lights are off in the hallway, and outside the hospital is dark (only illuminated by streetlights, with no natural light). However, when Cameron speaks to House in his office following this, it's bright broad daylight outside his office window. Then, when House drives home, it goes back to being dark. (00:40:32 - 00:41:46)
Continuity mistake: When Baby Shoes fires the gun at Joe, the first camera shot shows he's holding the gun with both hands. However, in the next camera shot he's only holding the gun in one hand. (00:01:55)
Character mistake: House tells Foreman to search the cop's home, car and workplace. He says that he will focus on the precinct. But the cop's workplace is the precinct.
Character mistake: Dates on a former patient's file indicate a birthdate of 04/24/24 and an admission date of 02/04/94 (an attained age of 69 yrs 9 months 11 days); House subsequently refers to that patient as a "73-year-old woman." (00:06:19 - 00:08:37)
TB or Not TB - S2-E4
Continuity mistake: When Dr. Cameron is walking with Dr. Charles to go for a procedure, he barely has any facial hair before they enter the stairwell, but once they reach the stairwell his facial hair has increased quite a bit. His hair is also parted to the left prior to entering the stairwell and once in the stairwell it is parted on both sides.
Suggested correction: They don't use water as a coolant, but they can collect water that condensed from the cold inside the unit.
LorgSkyegon
Which still doesn't allow for legionella to breed, not least the limited amount of collected water drains away (i.e. not like in water tanks and cooling towers). Healthcare professionals have consistently confirmed that window AC units aren't legionella risks for this reason. If you check the CDC website, it explicitly states that window AC units aren't potential legionella sources.