Mario sick from the Bean Fever
“Hmmm... Green hue... Yes... Discoloration in the face... The symptoms seem to indicate... Bean Fever! No mistaking it!”
Toad doctor, Mario & Luigi: Superstar Saga

Bean Fever is a condition endemic to the Beanbean Kingdom. It causes whoever has it to gradually turn into a Bean in three days, although it is unknown if they turn into a Beanish Resident or a literal bean. Bean Fever can only be contracted by foreigners. It is caused by the consumption of unfamiliar Beanish food, one known food being the Invincishroom, or rather in the remake, what was thought to be the "Invincibility Mushroom" yet was actually a Poison Mushroom. Mario acquires this disease while in Little Fungitown during Mario & Luigi: Superstar Saga, prompting Luigi to go on a solo mission to find the cure in Guffawha Ruins, which happens to be Crabbie Grass. Unfortunately, Mario's bedridden state and Luigi's absence allows Cackletta, now revived as Bowletta after possessing Bowser, to abduct Princess Peach to restart her evil plans.

In Mario & Luigi: Superstar Saga + Bowser's Minions, the disease now reduces Mario's HP to 1 and his BP to 0.

Names in other languages

Language Name Meaning
Japanese マメねつ
Mame Netsu
Bean Fever

Chinese 豆豆热
Dòudou Rè
Beanbean Fever

Italian Febbre Fagiolina
Beany Fever