Bok choy, pak choi, pichay/petsay, or Pok Choi is a type of white stemmed Chinese cabbage. It is a good source of Omega-3, fibre, calcium and folate. Maximize the shelf life of bok choy, refrigerate in a plastic bag and do not wash until ready to use. Properly stored, bok choy will usually keep well for about 3 to 4 days in the refrigerator.