Mustard Greens: Cancer Prevention, Nodule Dispersal, Lung Moistening and Phlegm Resolution

Mustard greens are the tender stems and leaves of Brassica juncea and Brassica juncea var. gracilis of the Brassicaceae family. They come to market from May to October and are sold in most vegetable markets across the country. Mustard greens have a slight bitterness, but a lingering sweetness after the bitterness, and taste quite good.

Mustard greens have a good cancer-preventing action. Testing their cancer-preventing and anti-promotion activity with the Epstein-Barr virus early antigen (EBV-EA) induction inhibition assay showed that mustard greens have a very high inhibition rate against cell carcinogenesis.

TCM has a long history of using mustard greens as medicine. The Mingyi Bielu, compiled by Tao Hongjing of the Liang dynasty, records that mustard greens "mainly remove kidney evil qi, free the nine orifices, brighten the ears and eyes, quiet the center, and long-term use warms the center." The Bencao Gangmu (Compendium of Materia Medica) says mustard greens "open the lung and expel phlegm, free the diaphragm and stimulate the appetite." The Sui Xiju Yinshi Pu says they "supplement original yang, free the lung and expel phlegm, harmonize the center and free the orifices; pickled is even better."

Here pickled mustard greens are advocated as having better medicinal effect, but today we do not recommend pickled foods because the nitrite in them is a group-1 carcinogen. In antiquity, not only pickled mustard greens were used as phlegm-expelling medicine, but even the pickling brine was used medicinally. For example, in the Qing dynasty Wang Hongxu, in his Waike Zhengzhi Quansheng Ji, introduced a method for treating excessive phlegm and drool: dip a goose feather in the pickled mustard brine, touch the throat to induce vomiting.

Mustard greens are not without drawbacks. The Shaoxing Bencao says mustard greens, "if eaten in excess, readily induce various diseases." The Riyong Bencao says, "those with hematochezia or hemorrhoids should avoid them." The Bencao Gangmu also says, "long-term eating accumulates warmth into heat; too much pungent dispersion consumes one's true origin, harms the liver wood, clouds the eyes, and triggers hemorrhoids." Overall, traditional TCM considers mustard greens a pungent-warm food; those with yin deficiency and fire hyperactivity, or eye diseases, sores or hemorrhoids should use them cautiously.

But besides freeing the lung and resolving phlegm, mustard greens' greatest action is reducing swelling and dispersing nodules, and they indeed inhibit cancer cells. In antiquity they were mostly used to treat breast abscess and ulcerated swollen painful gums. Although internally eaten mustard greens can trigger hemorrhoids, mashing mustard leaves and applying them externally to breast lumps and hemorrhoids can treat breast abscess and hemorrhoids. Mustard stems burned to ash for external use can also treat ulcerated foul gums. Mustard greens decocted for external washing can treat allergic dermatitis.