When a child reveals the existence of their fairy or fairies, all witnesses and the child have their memories wiped by Jorgen, and all magic items they have come in contact with disappear. This is the second largest rule.
If no kids in the world are miserable, Pixies can grant wishes (in this condition, all the fairies on the Earth will be pulled back to Fairy World).
No godchild can wish for their fairy to have a baby (it was meant to be made a rule after Cosmo was born, but Jorgen forgot to enforce it. He had written it down on a sheet of paper, but and never officially put the rule in the book, so it was legal, thus allowing Cosmo and Wanda to give birth to Poof).
A child's fairy cannot tell them what other kids have fairies--the child has to find out on their own. Although the child can wish to know if a certain person has fairies (proven in "Fairy Fairy Quite Contrary", Timmy wishes for Wanda to tell him if that Remy's godparent knows her).
A child can't wish to take away the fairies of another child. They have to be wished away by the same child, or compete in a Magical Duel.
Fairies only grant wishes to miserable children of the dominant species of Earth.
Magic can't be used to win a contest, only for showing off (unless it is a Magical Duel).
No 'Super' wishes. (Not in da rule book, but a small rule created by Cosmo and Wanda for Timmy.)
Can't wish for a world without girls. (rule was also caused by Timmy)
Can't wish for someone to get hit by a car.
If you try to wish a "lost deed", it would be considered falsifying documents.
If your life is perfect enough or you say "I'm happy and don't need my godparents anymore," they must leave the child and be assigned to a miserable one. (proven in "The Switch Glitch")
Wishes can only be granted by the child, unless the child wishes for his fairies to grant someone else's wishes. (Timmy has lent his fairies to Tootie, Carl, Sheen and Libby)
All vocal wishes shall only be made in the voice of the godchild only.
Tooth-based wishes can only be approved by the Tooth Fairy. (proven in "Shiny Teeth")
Can't wish for bad things and non-lethal things to happen (maimed, injured, beaten, or dead). (Timmy broke this rule a bit in "Boys in the Band".)
No wishing dead people back to life. (It is allowed to wish for a ghost, however, as Timmy was able to make pirates come to Dimmsdale in "Wish Fixers" to make them tell a story. Timmy has however broke this rule when bringing King Arthur back to life when he is killed by the Dragon in the episode "Knighty Knight", but the rule may have been caused from the wish in "That's Life" (which occurs after Knighty Knight) because the undead zombies nearly tried to kill Timmy and his parents.)
Cloning wishes can only be canceled when all the clones are in the same room and at the same time.
One day in a certain number of years, a fairy godparent has to be "bad" and if in the bad day that fairy godparent can't able to be bad then that fairly have to train to be a fairy again in five hundred years at the Godparents Academy.
If all Fairy Godparents in the universe want to have the same godchild, all the fairies must compete in a Rage in a Cage match, and the winner will have the wanted godchild.
Whomever has a wand has complete control over it, meaning you can't wish it back, and whomever has the wand has the power to grant their own wishes and the wishes of others, meaning you'll have to get it back the old fashioned way. (According to Da Rules, this rule is called the Finder's Keepers Law) (This rule was proven in the episode "Where`s The Wand").
Any rule of Da Rules can be removed if one of the fairies "accidentally" cuts a page. (Proven by Cosmo in "Movie Magic")
You can't wish away Da Rules or wish away any of the rules. (Including this one)
If a kid can't be trusted to keep their fairies a secret, then they can't have their own fairies, no matter how miserable they are (they can still have someone else's fairies temporarily loaned to them if they are twice as miserable as that kid who has the fairies).
No wishing away what can last forever. (it is almost impossible even with magic due to their properties)
No undoing wishes for something authentic.
Fairies must always grant the wishes of the godchild when they say "I wish".
No wishing for an electric car.
If a fairy godparent quits, the position can be filled by any magical wish granting creature.
If a fairy stays in the dark for more than eight hours, they will turn into a monster. (First of all, this is a fact, and also, Timmy's fairies just made this up to scare him for scaring Poof)
Fairy magic has no effect on Roaches.
No wishing for Tom Cruise.
If a godchild accidentally wishes to break Da Rules so badly, then let the next person touches Da Rules, that person will steal all of the wish power of the fairy stupid enough to grant such a silly wish. If that fairy and the godchild want to get back the wish power, then they have to return all the pages of Da Rules in 49 and half hours after the wish was granted and if they don't return all the pages, the godchild will have to face The Ultimate Challenge. If the godchild fails to complete the challenge then the godchild's fairy/ies will lose the fairy licenses forever (This rule was proven in the game Fairly Odd Parents:Breakin' Da Rules).
If a fairy lost their copy of Da Rules then that fairy must go back to Fairy World to train to be a fairy again in Fairy Academy for 500 years (This rule was proven in the PC game Fairly Odd Parents: Breakin' Da Rules).
No wishing away awful/potentially fatal diseases, such as cancer.
If the godchild had injured a holiday icon then that godchild must fix all the consequences that has caused. This rule was proven in A Fairly Odd Christmas)
Nobody but Jorgen Von Strangle can write in Da Rules.(Made after the events of Cosmo Rules)
If a fairy fails inspection, they have to go to The Fairy Academy to train for a millenium.
IF YOU MAKE A SECRET WISH, YOU WILL BE PUNISHED HORRIBLY. THIS IS THE LARGEST RULE. (Details in Ultimate Violation section)
Can't wish for someone else become non-existant. (Cosmo break this rule in episode I Dream of Cosmo)
If a fairy let an anti-fairy steal their copy of Da Rules then that fairy will be demoting to Fairies 3rd Class (when the fairy is demoing to Fairies 3rd Class their wish granting powers are very limited) until that fairy get the book back. (Both rule 53 and 54 are proven in Fairly Odd Parents: Breakin' Da Rules)
You cannot wish for yourself or other people to not age. (proven in Timmy's Secert Wish)
Note: These rules have been marked the the TV shows. There are likely way more rules in Da Rules book.
"If there ever was a boy named Timmy Turner, who has kept and loved his fairies for over 13 years, and saved Fairy World on more than a few occasions, and if he promises to make wishes ONLY FOR OTHERS and not for his own selfish purposes, he can KEEP his fairies."(Cosmo, Wanda, and Poof)
There seems to be variations to losing your fairy/ies depending on how the child acts them out.
If the fairy/ies are revealed by the godchild on purpose, Da Rules will appear and the fairy/ies will be sucked into it, but the godchild and everyone around will remember they exist and everything they caused will remain the same. Despite this, Crocker and afew other people seem to be aware of Timmy's godparents without any consequence.
If the fairy/ies are taken away by the fairy court, the godchild will never see them again, but will still remember them, and everything he or she had from them will remain. There is also the possibility of the godchild retrieving their fairy/ies if proof is found that he or she is worthy of having them.
If the fairies are accidentally revealed (as proven by Timmy, Cosmo, and Denzel in "The Secret Origin of Denzel Crocker), the Fairy Council and Jorgen Von Strangle will appear and take them away. They will wipe the godparents' memory, the godchild's memory, and the memory of anyone involved. Everything he or she wished up will remain, however, but if someone spots a godchild's fairy godparents but they don't figure out who's fairy godparents they are, or the godchild they belong to, they don't have to go away forever (proven by Wanda in Information Stupor Highway,) but fairy godparents don't have to go away forever if they are seen by something that is not a person. However in Pipe Down, Crocker saw Timmy's fairies but they didn't go away forever although this could be because he couldn't get anybody to see them due to the meteor.
If the fairy/ies quit, the godchild will receive the ultimate punishment if the fairy/ies have had it with the child because he or she treated their godparents so badly. Jorgen will erase the god kid's mind, very similar the punishment above, however, he will also take away EVERYTHING the fairy/ies ever gave the child, as seen in "Fairy Idol". After this, the fairy/ies and any other magical being will be able to go through a "Fairy Idol" and if the winner is not a fairy, he or she will become one, and will be assigned to the most miserable child on earth (unless said child happens to be the same one that said fairies were assigned to before he or she quit), in an attempt to make him or her happy.
If a fairy is challenged by another fairy or a godkid to a Magical Duel (proven by Timmy in "Fairy, Fairy Quite Contrary, even though Remy ended up lucky and secretly got his memory back from Juandissimo,), the loser's fairy/ies will be taken away from his/her/their godchild, who will forget he or she ever had godparent/s.
If the godchild grows up and becomes too old for his/her fairies (proven many times, Most notably in Channel Chasers and A Fairly Odd Movie: Grow up Timmy Turner!) the most peaceful way to lose you fairy godparents and is the right way to do so. It is the way it is supposed to happen in the first place, the godparent/s will pack their bags and leave their godchild once he or she outgrows them, and leave in the fairy cab (in Channel Chasers) or simply fade away (in A Fairly Odd Movie: Grow Up, Timmy Turner!, most likely because Timmy was proven grown up in a much different way than in Channel Chasers). The godchild will keep everything he or she had from the fairy/ies but will have his or her memory wiped without physical or mental damage. Any device that requires magic will power down and become an ordinary object. Whatever animal the godparent/s disguised themselves as during their time with their godchild/ren will be replaced by a normal version of the animal. It usually happens around the age of 18, which, in the US, is when a person is legally considered an adult. But, if the godchild keeps acting like a kid, even after he or she "grows up", it isn't against Da Rules, so he/she maintains his/her fairies.
If the godchild experiences life's true magic, love (proven by Jorgen in "A Fairly Odd Movie: Grow Up, Timmy Turner!"), after the godchild's early 20s (because 10-years-old Timmy has romantic moments with Trixie and Tootie and nothing happens), the fairies fade away from him.
If the godchild leaves home (proven by Jorgen in "A Fairly Odd Movie: Grow Up, Timmy Turner!") that is, if he starts living without his parents/guardian(s), the fairies will be lost.
If the godchild wishes he or she were an adult (Proven By Timmy in "The Big Problem") . In the most rare occasion, the fairy bell boy will let the godchild keep their fairy/ies until they are reassigned, and will only make exceptions through a bribe. The Fairies also cannot grant any wishes while the godchild is an adult. The godchild will have a chance to prove he or she's still as childish as always in an attempt to keep their fairy/ies. Although this rule contradicts the previous one, when the godchild becomes an adult, he or she is suppose to immediately forget about their Fairies.
If a wish is made for another species to become the dominant species of life on Earth, the fairies are reassigned to become that species's godparents
If a godchild says: "I'm happy and I don't need my godparents anymore" (Proven by Vicky In "The Switch Glitch"), they will instantly be taken away from the godchild who owns the fairy/ies, and have a smile stamped to their face. However, the godchild does not forget about the fairies afterward, because in that episode, there was no evidence that Vicky forgot about Cosmo and Wanda. In fact it was pretty obvious that she did remember having them, considering the fact she complained about how miserable she was without them.
If a kid has fairies loaned to him/her, then the godchild who loaned them will get them back at the day and time he and his godparent(s) agreed upon and the kid who had the fairies loaned to him/her will forget that he/she had them when the time runs out. But he or she will still have everything that they wished up. (proven by Tootie)
If someone makes a secret wish (like Timmy's and the 1986 Little John Applebee did), the godchild will get the ultimate punishment that includes: his/her memory will be wiped out by Jorgen, the godchild will never experience having fairy/ies, all of his/her wishes will be undone (including his/her secret wish), those wishes will be sent to Hocus Poconos, their life will be 10 times as miserable and you will not be allowed to loan your fairies to that person. This wish is counted as the ultimate violation of Fairy Law because the godchild might wish something that will cause catastrophe without being known with the fairy council. (From "Timmy's Secret Wish!")
If Cosmo and Wanda try to wish Timmy up something that doesn't apply by the rules, their wands will wilt and make a farting sound, sometimes when their wands malfunction, the same thing happens. (Example: Land Before Timmy).
In Season 0 in the pilot episode, The Fairly OddParents! (episode), Da Rules was colored yellow and the text was colored orange and was changed when it entered season 1. It is also Da Rules' first appearance. Since its change in season 1, Da Rules is now colored purple and the text is colored yellow
Almost all of these rules have affected Timmy in some way, and he has lost or nearly lost his fairies in most of the ways listed possible above. However, he always regains his fairies by the end of the episode/movie.
In the past seasons, it was said that each fairy has their own copy of Da Rules. But recently in recent episodes, they have it where there is only one official copy of the book.
In Hassle in the Castle, Cosmo and Wanda made up a rule that Timmy wasn't allowed to come into their castle because they didn't want to spoil the surprise about the Hall of Timmy.
There was made a live-action "Da Rules" book, for A Fairly Odd Movie: Grow Up, Timmy Turner!. Here a special loophole is made for Timmy in gratitude for his loyalty to his Fairies and his saving Fairy World on several occasions. It allows Timmy to keep Cosmo, Wanda, and Poof, so long as he uses their magic for the good of other people. In addition, Tootie is allowed to know about their existence and presence.
In the Episode Cosmo Rules, when Timmy started altering the contents of Da Rules, the world was in chaos. Jorgen mentioned that if the chaos continues, Da Rules will burst and destroy the entire universe. That being said, the greater purpose of Da Rules is to keep the universe together.
Only Von Strangles (meaning having their blood line) can contain the magic in the rules, as stated in Cosmo Rules.
in the old cartoons, Da rules was actually covered yellow and not purple.