Fever Fudge is a type of sweet made by [[Fred]and George Weasley]] for their Skiving Snackbox. Fever Fudge is designed to make the eater get a high fever within seconds of eating it, but the side effects are large, pus filled boils. These boils may be eliminated with Murtlap Essence.
In the film adaptation of Harry Potter and the Order of the Phoenix, Fred and George drug Argus Filch with chocolates that might have contained Fever Fudge, as he is shown in Umbridge's office with large, pus-filled boils on his face.