Approximately 80% of the body is liquid, and much of this fluid must be pumped and filtered through the urinary system. By feeding too much protein, sugar etc, the kidneys can become overloaded, this in turn can affect the horse in many ways. (Bucking, napping, rearing, grumpy or biting when girthed up, etc.) 
The 500gm size product lasts 5-6 weeks per horse, helping to tone and flush the kidneys, herbs with diuretic action and help expel any build up of lactic acid. The herbs are a powder added to feed or can be mixed with water and syringed orally.