Revealing mistake: When Kelso hits Dr Hendrick's bike with his car at the end, you can tell it is not Kelso. While you can't make out his face, you can see that the man driving has dark black hair, while Kelso has light brown/grey hair.
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 Turk, JD and Carla are drinking wine , JD's glass is sitting on the table, when Turk goes to pour wine on JD the glass is in his hand.
My New Suit - S5-E18
Continuity mistake: As JD is unwrapping the patients head while talking to the Janitor, he completely unwraps the gauze and there is 3-4 inches of hair showing. The shot changes and suddenly the head has gauze on it again and only about an inch of hair is visible above the bandage.
Continuity mistake: Season 5-19, Episode: His Story III. While Carla and Turk are lying in bed at the start both of them keep changing positions between shots. Turk's left arm and hand also keep changing position between shots.
Plot hole: Season 5, episode 20 (My Lunch). One of Dr. Cox' patients needs a heart valve transplanted. Heart valves don't have to be transplanted from another person. They can be replaced by a metal valve, or the surgeon can create a new valve from a different part of the patient's body. There was no reason to wait for a donor valve when they had other options available.
Plot hole: In the season 5 episode "My Fallen Idol", it is a key plot point that Turk has a hard time hugging guys. However in the Season 3 episode "My American Girl" Turk openly gives another surgeon a hug after J.D. makes fun of him. It is not possible for him to have changed because it shows that even before they became doctors, Turk would not hug J.D.
Character mistake: In season 5, My Transition, Kim mentions that on her 1st ever 1st date, she sat in the back seat of her boyfriend's Miata, but that car is a 2 seater - there is no back seat.
Continuity mistake: Season 5-24, Episode: My Transition (1). The first time we see J.D. and the flyer about his deck, the flyer has a picture of J.D. looking straight ahead smiling and the writing on it reads "Old? Gay? Like Decks?" After J.D. rips the flyer off and shows it to the janitor, the picture of J.D. has changed to him giving a thumbs up and the writing has also changed to "Come and Chill at my big gay deck."
Answer: Dan was drinking beer and Cox feared that Dan might get so intoxicated he would fall asleep and drown in the tub.
Mortug