1. Promote blood circulation: ginger contains spicy ingredients, can stimulate blood circulation, promote blood flow, so that the body tissues and cells get more nutrients and oxygen.

2. Remove cold: Ginger has warming properties, which can drive away cold and increase the body's temperature, thus relieving cold symptoms.

3. Relieve cough: white onion contains volatile oils and mucilage, which has the effect of coughing and relieving cough, and can improve symptoms such as sore throat.

4. Improve indigestion: ginger can stimulate peristalsis of the digestive tract, increase gastrointestinal secretion and movement, and relieve stomach discomfort.

5. Improve intestinal function: Brown sugar is rich in a variety of nutrients, with laxative effect, can improve intestinal function.

The contraindications of ginger, brown sugar and scallion water:

1. Pregnant women: ginger has the effect of promoting blood circulation and increasing uterine contraction, which can affect fetal development when consumed by pregnant women.

2. People suffering from bleeding disorders: ginger and brown sugar both have the effect of promoting blood circulation, which can easily cause bleeding, so people suffering from bleeding disorders should be cautious.

3. People with gastrointestinal diseases: ginger stimulates the gastrointestinal tract and increases acid secretion, so it is not suitable for patients with excessive gastric acid and gastric mucous membrane damage.