This trope is when literary writing is seen as such poor quality that it's only fit to be used as toilet paper (or similar undignified uses).
Sometimes it really is that bad, but a common variation is an illiterate or less cultured person using a book for toilet paper or kindling because he genuinely can't see any other use for it. In this version, don't be surprised if the book was a gift from an intellectual character.
This is often a comedy trope, but not always. Saying another person treats a given text like toilet paper can be serious, depending on how serious the text in question is. A politician who says a rival "may as well be wiping his rear with the Constitution" is asking for a fight.
If the text in question is real, there's often an element of Take That! present.
Before the availability of cheap purpose-made toilet paper, people commonly used old paper for wiping purposes. The rural outhouse with last year's mail-order catalog hanging next to the seat is Truth in Television, but not this trope because the catalog had value, it's just on its final cycle of usefulness.
- Implied in a joke from Sayonara, Zetsubou-Sensei, showing a bookstore next to a pet store with the comment that you don't want to know where unsold manga ends up.
- Airheads: A disgruntled band is holding a radio station hostage, and one of their demands is a record contract. Once they get one, the leader realizes the terms are pretty poor and shows his displeasure by wiping his ass with the contract.
- Dances with Wolves: After Dunbar goes native, his journal is found by some illiterate soldiers and used for toilet paper.
- In The Day After Tomorrow some survivors are trapped in a library and need a fire to stave off the lethal cold. Although hesitant to burn books, they decide to start with the tax code as it's quite large and no one's going to miss it anyway.
- Demolition Man: John Spartan can't figure out how to use the Three Seashells that have replaced toilet paper in the future. So he goes to have a little chat with a machine that dispenses citations for foul language.
- Dunkirk starts with a group of British troops walking through a blizzard of German propaganda leaflets declaring "YOU ARE SURROUNDED". One of the soldiers grabs one and goes to find a place to take a dump.
- At one point in The Belgariad, Queen Layla subtly invokes this trope when she uses a treaty to wipe jam off the face of her youngest child. (The ambassador gets the message, but can't call her out on it.)
- CHERUB: In one book, two CHERUBs on a training mission in the wilderness are given knapsacks filled with seemingly random supplies, including an apparently useless copy of The Complete Works of Shakespeare, which they leave on the beach they were dropped off at. It's only later, in the jungle, that they realize the book was included with the intent for the pages to serve as toilet paper.
- There's a couple of references to this in Discworld. It's indicated that the only book Cohen the Barbarian had ended up as toilet paper. Also, the Discworld Almanac indicates that the work, existing in-series is used as toilet paper by the people of Lancre- basically, they don't have a lot of use for a book recounting their superstitions and farming techniques.
- In The Royal Changeling by John Whitbourn, the hero's wife tells her eldest son to take a particular letter and place it will it will do the most good, i.e. in the privy.
- Inverted in A Series of Unfortunate Events: The Penultimate Peril. Seeking to convict greedy injustice causers, Jerome Squalor writes a book documenting the crimes he uncovered, titled Odious Lusting After Finance. However, the greedy Count Olaf shows how little he cares about books when he uses it for kindling to start a hotel fire. He remarks that it's the only way it's useful, but the Lemony Narrator laments watching the words burn.
- In the Sven Hassel novels, Tiny's mother ends up using the Your Fuhrer Thanks You card she got notifying her that one of her sons had died 'fighting bravely' for Nazi Germany. Not out of contempt but because nothing else was available. Her thoughts towards the Fuhrer were rather unpleasant given how hard and rough the card was.
- Blackadder Goes Forth has the "inspirational" magazine for the British troops, King and Country, that Blackadder calls "soft, strong and thoroughly absorbent."
- Referenced in Malcolm in the Middle when Hal enlists uber-nerd Craig to help him pick out a comic book for Malcolm's birthday gift. He dismisses one the shopkeeper recommended by saying "I'd keep this in the bathroom... but not for reading."
- Salute Your Shorts: One episode has Sponge trying to hand out issues of his camp newspaper. Donkeylips asks for one, then blows his nose on it. Another episode has Deena signing (unwanted) autographs on anything handy after finding out she's gotten the lead in the camp's play, including Donkeylips' napkin. He just shrugs and blows his nose on it anyway.
- Space: Above and Beyond: In at least one episode, a character takes a copy of Stars and Stripes (a US military newspaper) with him to the latrine, with a jokey tone strongly implying they're not planning to read it.
- Monsignor Renard. The title character is found with German propaganda leaflets on his person and is accused of being a subversive. He explains he kept them for toilet purposes. "It seemed appropriate."
- Not toilet paper, but one episode of The Navy Lark reveals that most of the memos from London get treated as drinks coasters because the things they are declaring are so useless. One example given was that London decreed that "when approaching harbour, pilot vessels should fly at no less than 2,000 feet", prompting Admiral Ffontbittocks to declare that he'd never seen an airborne tugboat yet.
- World of Warcraft: A quest in Theramore has you trying to discredit some dissidents undermining Lady Proudmoore with "creatively edited" versions of their flyers. One of the reactions you can get handing them out is that it might be useful in the latrine.
- Saturday Morning Breakfast Cereal discusses this trope here, where a character asks if it's a coincidence that art degrees are put next to particularly low-quality toilet paper.
- Subnormality presents the No-Bullshit Emporium, which sells copies of L. Ron Hubbard's Dianetics pre-printed on rolls of toilet paper, available in both regular and quilted.
- On Family Guy, Peter discovers that there's no toilet paper, but is then relieved that there are some Entertainment Weekly issues nearby. (At the time, Entertainment Weekly had Family Guy in its list of worse TV series of the year.)
- Spongebob Squarepants: In the live-action segment of the episode "Party Pooper Pants", Patchy the Pirate tried to invite Spongebob and Patrick to his party via invitation. The problem is that they can't read it because the ink smears underwater, so they threw it in the campfire. Underwater.
- Rudolph Louis (music critic for the Muchner Neuste Nachrichten) wrote an uncomplimentary review of one of composer Max Reger's works. Reger wrote to Louis:
I am sitting in the smallest room of my house. I have your review before me. In a moment it will be behind me.
- Count Dmitry Khvostov self-published his poetry because publishing houses refused to. There's a Russian story claiming Ivan Krylov was once in dire need of something for wiping purposes while outside, and was "saved" when the count drove past with some copies of his latest book.
- During WWI in Tanzania, the isolated German colonial army used obsolete documents (maps, letters, etc) as toilet paper. An eccentric British intelligence officer dug up their latrines to retrieve a wide variety of useful, if outdated, information.