Guinea pigs can eat cabbage, although they should only be given no more than approximately 1/3 pint per day. The rest of the guinea pig's diet should consist of grass and hay, which both must come from high-quality sources.
It is also recommended that in addition to the grass, hay and fresh greens such as cabbage, the guinea pigs should be given commercial grade nuggets. The amount will depend on the nuggets chosen, so the guidelines on the box should be followed. If an owner wants to feed their guinea pig a different type of food, asparagus, Brussels sprouts, carrots, cauliflower, celery, kale, parsley, radish, turnips and tomatoes are all healthy and safe for guinea pigs. The leaves on the tomato, as well as rhubarb and potatoes need to be kept away from guinea pigs as these are not safe food choices.