The functions of Cao Guo include drying dampness and removing cold, expelling phlegm and intercepting malaria, strengthening the spleen and opening the stomach, and inducing diuresis and swelling. Grass fruit has the effect of drying dampness, warming the middle and stopping malaria. Grass fruit is the mature fruit of the perennial herbaceous plant grass fruit of the ginger family, in the fall when the fruit begins to mature, the fruit becomes reddish-brown, not yet cracked when harvested, sun-dried or dried. Sexual flavor: pungent, warm, non-toxic. Attributed to the spleen meridian, stomach meridian.

It is the cold and dampness of the spleen and stomach appearing in the epigastric cold pain, fullness, nausea, vomiting and diarrhea, you can use grass jelly to treat. At the same time, grass fruit also has the effect of treating malaria of the cold-damp type. The Compendium of Materia Medica states that "Grass Fruit warms the spleen and stomach, stops vomiting, benefits the true qi, eliminates all cold qi swellings, and also eliminates dormant food and detoxifies alcohol." The usual dosage of Cao Guo is 3 to 6 g.