This item is found only in the console version(s) of Terraria.
The Cabbage is an item used to summon the Guinea Pig, a pet in the console and mobile version. Cabbages are uncommonly found in chests scattered around the world and as rare drops from Snatchers. In the Xbox 360 version, cabbages seem to be more commonly found in Jungle biomes. The Pet Guinea Pig will not attack anything, and it will fly and fall in the same fashion as most other pets.
In the iOS version, Cabbages are incredibly common in overworld chests.
In mobile, trying to spawn in a Carrot for the Pet Bunny will only result in the player receiving Cabbage.
Even though cabbage is used to get a Guinea Pig in-game, in real life, cabbage isn't healthy for guinea pigs.
The Guinea Pig and the Pet Slime are very alike in movement.