Chao kuay is a black vegetable jelly, made by boiling the aged and slightly oxidized stalks and leaves of the plant Mesona chinensis, with potassium carbonate and a little starch.

When cooled the decoction becomes a translucent black jelly, which in English is known as grass jelly. It either mixed with crushed ice and palm sugar and eaten as a dessert, or mixed with soy milk to create a drink.