Continuity mistake: When Elliot is crying to get her own way, her hair changes from hanging loose to tucked behind one ear, and back again.
Revealing mistake: In the scene where J.D. first starts the bike portion of the triathlon, you can see his feet pedaling. You can see that there is no chain on the gears, allowing him to exaggerate the speed he is pedaling.
Character mistake: JD is having problems with someone dressed in a gorilla suit, who is slightly shorter than he is. JD sees the janitor, who is considerably taller than he is, eating a banana and accuses him of being the gorilla. If the janitor were as tall as JD, maybe, but you would not confuse someone shorter than you with someone taller, regardless of costume.
My Old Friend's New Friend - S4-E1
Continuity mistake: Right after Elliot asks Molly about the patient, you can see the Janitor standing next to the table behind Molly. But in the close-up shots on Molly, he is gone.
My Old Friend's New Friend - S4-E1
Continuity mistake: In the end, when Carla comes out of the hospital and sees the Mini Cooper, JD's hands changes between shots. In one of the far shots he is holding the handles on his scooter, but in a close-up shot he is holding his helmet.
My Last Day - S1-E24
Continuity mistake: When Jordan approaches the table, Elliot is seeping her tea bag. But when it cuts to Jordan her hands are around her cup with no tea bag in sight. (00:20:20)
My Best Friend's Baby's Baby and My Baby's Baby - S6-E2
Continuity mistake: When Jack asks Perry what is on the screen, Perry's arm moves from the back of the sofa to his lap in an instant cut.
Continuity mistake: When JD opens the beer can with the "John Dorian three taps method" inside Dr. Cox's car, he holds it in the hand in different ways.
Continuity mistake: When JD gets hit by the blue paint and confetti by the Blue Man Group at their concert, most confetti in the next scene disappears and JD is almost covered only by paint.
Continuity mistake: When JD is trying to free his hand from the glass bottle beating it on the pole, his sleeve shirt is first lowered and then raised in two different shots.
Continuity mistake: At the beginning, the doctors do the race to get the board member patient. They take the lift from the 4th floor. When they get out of the lift, they are still on the 4th floor.
Our Thanks - S9-E13
Continuity mistake: When Dr Cox "wins" the "pinball game" with Denise about what Trang is to do, he leans in to him and says "go go go." The next shot of Trang running off has Dr Cox standing straight upright.
My Absence - S8-E9
Continuity mistake: Elliot slips her phone in Dr Cox's left coat pocket. When he hears JD's voice later when his coat is over the back of the chair, he pulls the phone from his right pocket.
My Drive-By - S4-E24
Continuity mistake: When Dr Cox, Turk and Carla are talking about what happened at the Taco stand, at some point a pen suddenly materialises on the desk. None of them were holding a pen either. (00:10:25)
My Drive-By - S4-E24
Visible crew/equipment: When Doctor Cox looks at himself in the gold balloon each time, look slightly to the right of the shot, you can see the camera and part of the camera man in the reflection. (00:08:00)
Other mistake: Elliot told Kelso that he was getting a chocolate cake for his birthday, because she likes chocolate cake. At the party, the cut cake that everyone is eating is white. (01:42:00 - 02:04:00)
Continuity mistake: When JD is in the wheelchair talking to Dr Cox and he almost tells him he was a gymnast in high school, a female doctor in a white coat is walking in his direction behind him. One shot later she's gone, and a few shots after that she's back walking in the same direction. (00:02:55)
My Lucky Day - S2-E9
Continuity mistake: The clock skips about ten minutes ahead when Dr. Cox throws J.D. his chart. (00:06:25)
Answer: Dan was drinking beer and Cox feared that Dan might get so intoxicated he would fall asleep and drown in the tub.
Mortug