Star Cures
The three Star Cures are the ultimate goal for much of the second half of Mario & Luigi: Bowser's Inside Story. Mario and Luigi first learn about the Star Cures from Dr. Toadley shortly after a fight with Bowser. Each of the cures are held by a Star Sage, whom the bros. had to convince to retrieve.

Toadley tells the Bros. that the first vaccine is held by Durmite, who is usually located in Dimble Wood. However, the Marios had already found and beaten Durmite in Bowser's body. They discover that Durmite is still inside his body, and begin to pursue her. After a battle, Durmite, whose real name turns out to be Wisdurm, relinquishes the first Star Cure on friendly terms.

The second Star Cure, as it turns out, had come into Bowser's possession before the events of the game, although the sage it was originally under the possession of was the Koopa Kuzzle. He travels to a vault below his own castle to retrieve it. He is forced to do battle with the Fawful Express for the Star Cure. Mario and Luigi then need to reconstruct Bowser's damaged memory of the combination to the Star Cure's vault. When Bowser opens the vault, however, three traitorous minions, Private Goomp, Sergeant Guy, and Corporal Paraplonk, shove him inside. Frustrated, Bowser swallows the Star Cure. Starlow notices this and suggests that the Marios escape with it through a warp pipe.

The final Star Cure is held by Chakron, of Plack Beach. He gives it to the Marios after they successfully knock him out of his "1000 year pose" using Snack Basket.

When all three Star Cures are brought back to Doctor Toadley, he combines them into the Miracle Cure, which cures every Toad that has contracted the Blorbs. It also breaks the barriers outside Peach's Castle, allowing the Marios to enter both the castle and the final stretch of the game.

Interestingly enough the star cures are the same color as the playable characters in the game. (I.E. Red for Mario, green for Luigi, and yellow for Bowser.)