Chloride is one of the most important electrolytes in the blood, along with sodium, potassium, and calcium. Chloride helps keep the amount of fluid inside and outside of cells in balance. It also helps maintain proper blood volume, blood pressure, and pH of body fluids.

Most of the chloride in the body comes from table salt (sodium chloride) in the diet. Chloride is absorbed by the intestines during food digestion. Any excess chloride is passed out of the body through the urine. Chloride levels in the blood generally rise and fall along with sodium levels in the blood.