Contraindications (禁忌):

Yin Deficiency with Heat signs (阴虚有热) — its warm, pungent nature can further deplete Yin and aggravate Heat
Stomach Fire or Stomach Yin Deficiency — can irritate the stomach lining and worsen conditions like gastritis or ulcers
Heat in Blood patterns (血热) — may exacerbate bleeding or inflammatory conditions
Pregnancy — strong pungent herbs that move Qi vigorously are generally avoided

Cautions:

Excess use can injure Qi and Blood — overly pungent herbs disperse, and prolonged use may weaken the body.
Digestive sensitivity — can cause stomach upset, heartburn, or diarrhea in sensitive individuals
Skin and mucous membrane irritation — topical use or excessive consumption can cause burning sensations
Hyperthyroidism — like other Brassicaceae plants, contains goitrogens
Use with caution in those with hot constitutions (热性体质)