This episode was originally entitled "Little Creatures".

This episode was nominated for the 2006 Emmy Award for Outstanding Makeup For A Series.

Constance: Dont worry, I only killed 3 people and none of them were doctors.

Meredith: (Voiceover) Four hundered years ago, another English guy had an opinion on being alone. John Donne. He thought we were never alone. Of course it it was fancier when he said it. No man is an island entire onto himself. Boil down that island talk and he just means that all anyone needs is someone to step in and let us know we're not alone. And who's to say that someone can't have four legs. Someone to play with, or run around with, or just hang out.

Meredith: So, you're giving up your trailer.
Derek: I am not giving up my trailer.
Meredith: So you are still you?
Derek: I'm still me.

Olivia: I'm sorry, I still get a little squeamish around leeches.
George: Really? That is not what I have heard.

Karl: But sometimes, no matter how much you love someone, they just can't love you back in the same way. Believe me, son. Living with a woman who can't love you back...way lonelier than being alone.

George: By the way, uh...Sorry you had to see that little scene earlier.
Karl: Oh, you mean talking with the girl who isn't your girlfriend about the girl who you'd like to be your girlfriend?

Episode Title: Owner of a Lonely Heart

"Owner of a Lonely Heart" is the title of a song by the band Yes.