Ague

Ague is a magical ailment with symptoms that likely involve fever and shivering, similar to the Muggle illness of the same name. Information about this condition is extremely limited, as it does not appear in the original seven novels and is known only from supplementary material.

The only known reference to ague in the Harry Potter universe comes from a side quest in the Game Boy Color version of the Harry Potter and the Chamber of Secrets video game. In the game, a Hufflepuff student is found in the Hospital Wing suffering from ague. Harry Potter is tasked with bringing the student a Pepperup Potion to cure him (video game).

The known cure for ague is the Pepperup Potion (video game). As this potion is primarily used to counteract the symptoms of the common cold, it suggests that ague shares characteristics with a severe cold or flu, such as chills, fever, and general malaise.

The term “ague” is an archaic Muggle English word derived from the Old French (fièvre) agüe, meaning “acute (fever)”. Historically, it was used to describe a malarial fever or any illness characterized by fits of fever, chills, and shivering. Its use in the wizarding world reflects the community's tendency to incorporate older or more traditional terminology.