Continuity mistake: As Cuddy is making the deal with House, how much time off from Clinic duty for a week off his vicodin, while the camera is behind Cuddy you can see there is bright sunshine on House's head. The shot switches to a camera behind House and now his head is shaded.
Factual error: A kid is being taken to surgery to remove a magnet he swallowed because it may be stuck in his upper intestine. House diagnoses that the magnet is already in the lower intestine by taking a scalpel and showing that it's magnetically attracted to the lower abdomen. Surgical scalpels are made of high grade stainless steel and are not attracted by magnets.
Plot hole: The doctors tell House that blood tests did not show anything wrong with the teenage boy, but near the end of the episode, he realises that it is naphthalene poisoning. Naphthalene poisoning is something that is easily noticed by doctors through blood tests.
Factual error: In an episode with a severely overweight patient who is thought to have diabetes, it is discovered he instead has Chagas disease. Cameron then informs the patient that he acquired this illness from his food when, in fact, Chagas disease is a protozoan that is spread through the bite of the triatomine bug.
Factual error: Amber triggers a fire alarm by heating the sprinkler with her lighter. Unfortunately that fire sprinkler doesn't detect heat (or smoke). The sensor is located between the ceiling lamps, about two meters from the fire sprinkler. (00:09:00)