Yes. Duckweed in watercress is a relatively common traditional Chinese medicine. It is cold in nature and has the effects of diaphoresis, diuresis and stranguria. It can be used to treat rubella, measles, edema and other diseases. If the above discomfort symptoms exist, this drug can be used for treatment under the guidance of a doctor, and it usually has a certain effect. However, you need to strictly follow the doctor's instructions, do not take it blindly without permission, and avoid taking too much or missing a dose. So it is edible.