Choi or Chinese cabbage can refer to two distinct varieties that are related to the Western cabbage, and are of the same species as the common turnip. Pac Choi, also referred to as bok choy or Chinese cabbage, is a Chinese leaf vegetable often used in Asian cuisine. The vegetable is related to the Western cabbage, and is of the same species as the common turnip. Joi choi is a common and mild-tasting variety of pac choi with dark green leaves and a white stem. Pak choi is fat and cholesterol free, and a good source of vitamin A, vitamin C, and folate.