The information provided here is not a replacement for a doctor. You shouldn't use it for the purpose of self-diagnosing or self-medicating but rather so you can have a more informed discussion with a professional TCM practitioner.
In Chinese Medicine dehydration can be treated by two herbs that we have on record. Here is the list below.
The two Chinese Medicinal herbs most likely to help treat dehydration
Why might Common Reed Rhizome (Lu Gen) help with dehydration?
Because it is a herb specifically indicated to treat dehydration as can be seen on Common Reed Rhizome's page.
Common Reed Rhizomes is a Cold herb that tastes Sweet. It targets the Stomach and the Lung.
Its main actions are: Clears Heat and promotes the generation of Fluids. Dispels Lung Heat. Dispels Stomach Heat. Promotes urination and clears Heat in the urinary tract. Calm the minds and stop vomiting.
Why might Ginseng (Ren Shen) help with dehydration?
Because it is a herb specifically indicated to treat dehydration as can be seen on Ginseng's page.
Ginseng is a Warm herb that tastes Bitter and Sweet. It targets the Spleen, the Heart and the Lung.
Its main actions are: Very strongly tonifies the Qi. Tonifies the Lungs and Spleen. Assists the body in the secretion of Fluids and stops thirst. Strengthens the Heart and calms the Shen (mind/spirit).
Other symptoms often associated with dehydration
Phlegm Vomiting Strangury Lung abscess Dyspnea Loss of appetite Palpitations Insomnia Impotence Restlessness