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.
Because it is a herb specifically indicated to treat childrens bedwetting as can be seen on Light Wheat's page.
Light Wheats is a Cool herb that tastes Sweet. It targets the Heart.
Its main actions are: Tonifies Qi and clears Heat. Stops excessive sweating.