From the Manufacturer:
Aqua-Flow™ offers a special combination of herbs and nutrients to provide excellent natural support for kidney and bladder function. Magnesium has been shown in clinical studies to have a beneficial effect in the kidneys and vitamin B6 enhances this effect. Potassium and sodium are essential to body functions involving fluid regulation and balance.
The plants in Aqua-Flow have a long history of use. Uva ursi (bearberry) is well known for its benefits on the urinary passages. Europeans are familiar with boldo for supporting healthy fluid balance. And Native Americans used goldenrod, which stimulates the kidneys to eliminate fluid.