Abnormal growth of the rat if too much is drunk
When Ron Weasley took his pet rat Scabbers to the Magical Menagerie because he looked ill, the witch behind the counter suggested Rat Tonic. Before Ron could pay, Scabbers was attacked and chased out of the shop by Crookshanks. Ron and Harry Potter followed. Hermione Granger stayed at the shop to buy Crookshanks and the Rat Tonic, which she later passed on to Ron.
Behind the scenes
- In the Game Boy Advance version of Harry Potter and the Prisoner of Azkaban, Harry must go into the Leaky Cauldron's cellar to find some rat tonic for Ron. When he finds it, he also finds a rat that has become engorged from over-consumption of the tonic, and must fight it in order to get what remains for Ron.
- Harry Potter and the Prisoner of Azkaban (First appearance)
- Harry Potter and the Prisoner of Azkaban (video game)