Remove any yellowing or wilted leaves from the bok choy head.
Cut the root end off off about 1 inch from the bottom. Do not cut too much off; just trim it enough to remove the thick stem. By removing this thick part, the vegetable cooks more evenly and the leaves can be separated.
Separate the leaves from the head and rinse once more, if necessary.
Slice the stalk lengthwise to create smaller stalks. Cut them into bite-size pieces for stir-fries. You can also keep the leaves and stems attached and cook them together, but make sure the stalks cook evenly.
Cut the leaves from the stems, if desired. Use a knife to cut the vegetable parts to an appropriate size, but make them uniform to ensure even cooking. In many recipes, cutting the stems to 1-inch pieces is appropriate. The stems or stalks should be cooked for longer than the leaves if the parts are separated.