1. species: Chinese kale is the root of annual mustard in Cruciferae, while kohlrabi is the stem of biennial mustard in Cruciferae, so one is mustard and the other is cabbage, which are two different vegetables.

2. Appearance: Isatis indigotica is bulb-like, with oval leaves, pinnately divided, and irregular blunt teeth at the edge; The shape of Chinese kale is similar to that of a bulb, but its leaves are rectangular with serrated edges.

3. Efficacy: Chinese kale has the functions of resolving phlegm and resolving food stagnation, clearing away heat and cooling blood, inducing diuresis and treating stranguria, and can be used to treat lung heat cough, hypertension, diabetes, sore throat, mammary gland obstruction, edema and other diseases. Radix Isatidis has the effects of clearing away heat and toxic materials, cooling blood to stop bleeding, inducing diuresis to reduce swelling, and can be used to treat cough due to lung heat, sore throat, jaundice due to damp heat, stranguria due to heat, etc.