Firefox 2’s inline spell checker has indeed made the web more readable by eliminating those reluctant spelling mistakes. Sometimes, if you’ve got a sluggish mouse, you may accidentally add misspelled words into Firefox’s dictionary. Fortunately, there is a way to remove misspelled words from dictionary, but it ain’t as easy as adding the word. Here’s how:
- Open the run dialogue (shortcut: windows key + R) and paste %APPDATA%\Mozilla\Firefox\Profiles. If Mac, navigate to ~/Library/Application Support/Firefox/Profiles
- Choose your profile folder which looks something like xxxxxxxx.default
- Inside that folder, you’ll find a file called persdict.dat.
- Open the file using your favorite text editor, find the misspelled word and delete it.
You can also add multiple words in a single shot using the same persdict.dat file.

wrote, on September 22nd, 2007
On Linux the folder is ~/.mozilla/firefox/profiles. For n00bs, ~ is your home folder.
wrote, on September 23rd, 2007
Thanks for the quick tip Jake!
wrote, on September 23rd, 2007
Interesting… Thanks for the tip! Can come in handy anytime
wrote, on September 23rd, 2007
persdict.dat is not found !
You can add or correct words just by editing the dictionary at C:\Program Files\Mozilla Firefox\dictionaries
This also makes the changes globally !
wrote, on February 26th, 2008
okay well idk how dis really wurks…..lol consider me da blonde of technology no offensie…………………..=]
okay well how do u do this 4rm 1 computer 2 anotha
huh ? huh?
im lyke omg im s0o0o0o0 lost…..lol
well me n mi chiquita r her just chillin…wonder how da H e double hockey sticks…omb 4giv me lord..plz
but how duz diz wurk???
HELP!!!!!!!!!
call me at 321-234-4567
wrote, on April 4th, 2008
Another example of why Firefox is superior to IE
wrote, on April 6th, 2008
hey man as i come to new pages of this blog i ckeep coming to know that this blog is really a useful thing
i also saved the page on my handy usb ……..to use anywhere
good work people……..
keep it up
wrote, on April 6th, 2008
Thanks so much for this quick “How To”! I accidentally added a word to this dictionary today, so I did a quick Google search and this was the first link to pop up. Very easy to follow and simply solved my problem. Thanks again!