White mustard, the seed that warms the Lung
Bai Jie Zi means “the seed of white mustard”: a straightforward name, whose whole point lies in the first character, 白, white. It sets it apart from its yellow cousin, Huang Jie Zi, which is a different species. It is the ripe seed of Sinapis alba, an annual of the cabbage family native to the Mediterranean basin, with bright yellow flowers. The seed is spherical, 1.5 to 2.5 mm across, greyish-white and finely reticulated. It is harvested from late summer to early autumn; Anhui and Henan supply the largest volumes, and an old herbal held seed from the North to be superior. Plump and even, it should have a frankly pungent taste.
Warming the Lung, breaking up Cold Phlegm
In Traditional Chinese Medicine, the seed is warm and has a single flavour, pungent, but taken to the extreme. Pungency opens and disperses; warmth warms. It enters the Lung and the Stomach. When Cold settles in the Lung, tradition says it congeals the Fluids into thick Phlegm; the warmth of the seed undoes this congealing, its pungency opens the way, and the Lung regains its downward movement. Li Shizhen saw two merits in it: moving Qi and dislodging Phlegm, warming the Middle and restoring the appetite.
Between the skin and the membranes
The texts credit it with a speciality: reaching Phlegm “between the skin and the membranes”, places that ordinary plants do not get to, and loosening what has gathered there. With perilla seed and radish seed, it forms San Zi Yang Qin Tang, the “three-seed decoction for caring for one’s parents”, devised under the Ming for the elderly. For internal use, tradition dry-roasts it, which makes its action gentler and more sustained.
Key benefits
Phlegm cleared & Middle harmonised
Warm and pungent, it clears cold phlegm and warms the Middle, restoring the appetite according to tradition.
Warmth & a warmed Lung
With its extreme pungency, the seed warms the Lung and the body when Cold settles there.
Qi in motion
It moves Qi and brings movement back where Cold and Phlegm have set into a mass.
