Dehydration causes an abnormal reduction in the volume of circulating blood. This has a number of adverse consequences, many of which are related to imbalances in the levels of electrolytes in fluids that normally are contained inside and outside of cells (intracellular and extracellular fluids). Electrolytes are natural chemical substances which, when dissolved in water or melted, dissociate into electrically charged particles called “ions”. Ions can be negatively or positively charged and can conduct electrical currents. The key positively charged ions in a dog’s body fluids (“cations”) are calcium, magnesium, potassium and sodium. The primary negatively charged ions (“anions”) are bicarbonate, chloride and phosphate. The concentration of electrolytes is carefully regulated, because electrolytes are critical to the normal metabolic activities and functions of all cells in the body.