- The musical selection played by Giles during his presentation with the overhead projector is "Danse Macabre", written in 1874 by Camille Saint-Sans (1835-1921). It is one of his most popular compositions, and a piano transcription of it was made by Franz Liszt, as well as a really creepy transcription for organ by Edwin H. Lemare. It was also used as the theme tune to a British TV program called "Jonathan Creek", starring Alan Davies and Caroline Quentin. Anthony Stewart Head was in the first episode as magician Adam Krauss. It was intended as a recurring role, but he had to give it up due to Buffy commitments and the part was recast.
- This episode was nominated for an Emmy Award for Best Writing in a Drama Series.
- Spike likes to crumble up Wheatabix in the blood he drinks.
- The newscaster in this episode is Carlos Amezcua, a real-life co-anchor on KTLA's morning news. The KTLA Weatherman, Mark Kriski, appeared in season 3's 'Amends'.
- Lindsay Crouse (Maggie) previously worked with Amber Benson (Tara) in the 1995 movie "Bye, Bye Love".
- This episode introduces Amber Benson as Tara, who will play a big part in the lives of the Scoobies, especially Willow's, over the next 2 years. In a chat interview Miss Benson said the scariest thing she has ever seen was during a lunch break where the Gentlemen (still made up and in costume) were eating lunch.
- The song that the girl sings in Buffy's dream at the start of the episode is sung to the tune of the song "Master of the House" from Les Miserables.
- Apparently the Gentlemen were inspired by a dream Joss had. Also, the reason they did an episode with almost no speaking was to force themselves to be more creative visually.
- LOOK HARD: Andy Hallett (Lorne from Angel) can be seen in the top left corner of Prof. Walsh's classroom during the opening sequence.
- Giles's drawing prowess is also used in season 7's "First Date" but with slightly less gratifying results, when he scares Cho-Ahn.
- 'Hush' was a gag episode - one made to show that you could still make silent drama compelling, but it was done so well that nobody laughed.
- Giles gets delivery of the Sunnydale Press, the same newspaper we saw in 'Bad Girls'.
- Joss stated in an interview at Ultimate TV that he had originally planned for Buffy and Riley to have sex in this episode, while they couldn't speak, but "it became clear that it was too early for that."

- When Spike opens the fridge, the cup of blood is full almost to the brim. When he starts to drink he tips it so far that if it were that full, it would have spilled onto him before it even got to his mouth.
- At one point, when Riley & Walsh are having their typed/written "conversation", the text on Walsh's screen changes for no apparent reason.
- Before Willow and Tara move the fridge. A close up shows the two gripping hands, when the camera backs up on the two a bit, they grip hands again.
- In the scene where Xander is on the phone with Buffy you can see a cross tattoo on his shoulder they tried badly to cover up.
- During Giles's presentation, when Xander is writing on his board, he tilts it a bit and we can see the words that have been prewritten.
- As the Gentlemen fly down the street look at the road in front of them, you can often see the shadows of the wires used to suspend them.
- Spike says he sometimes likes to crumble up the Wheatabix in the blood - "give it a little texture." But unless he's talking about the brief period that he's been "chipped" by the Initiative, this is a minor goof. Because before the Initiative thing, Spike never had to drink blood from a mug (and crumble up the Wheatabix), because he was still able to feed of a human.
- When Riley smashes the bottle near the end of the episode, a chunk of glass lands firmly on top of the box. When he starts to swing at the box, the chunk of glass is gone.
- Still in the same scene, Buffy holds her message board up to ask how she gets her voice back. When she first holds it up, the marker is in her right hand. After a quick cut away and back, the marker is in its little slot on the message board.
- As the scene in the lecture hall starts, Anya can be seen sitting down, empty handed, with no sign of popcorn nearby (and no reason for there to be, as they're clearly just entering the room). A moment later, as the camera cuts back, she's apparently pulled a bag of microwave popcorn out of her skirt.
- In the same scene, Buffy is mostly sitting with one leg up on her seat. But during a few camera switches, her keeps moving down and then up again. Some of the cuts are long enough to argue that she could be squirming around, but some cuts are too quick for that to be feasible.
- Spike wipes the blood off his mouth after Xander gets off of him (after he realizes that Spike didn't kill Anya), but in a shot a few seconds later, the blood is still there.
- At the end, when they show a shot of outside the campus, you can see Buffy in the bottom left corner of the screen. It is from the first episode of season four when she's outside looking confused (the scene with the colored folders).
- They walk past a guy with a sign that says "Revelations 15:1." That bible passage says: "And I saw another sign in heaven, great and marvellous, seven angels having the seven last plagues; for in them is filled up the wrath of God." This fits with the 7 hearts that are being stolen, yet the doom-sayer doesn't know anything about this. Wouldn't it have made more sense to choose a bible passage that talks about silence or inability of speech?