Metabolic alkalosis is an acid-base disorder in which the blood becomes too alkaline. In bulimia nervosa patients, it often results from purging, which depletes both potassium and intravascular volume, and is worsened by hypokalemia. In turn, this causes aldosterone levels to rise, which makes the kidneys absorb more sodium and chloride while excreting more potassium through urine. Purging also causes hydrogen ions to be lost, raising the body's pH. While normally bicarbonate is excreted to correct this alkalemia, bulimia nervosa patients may not excrete as much bicarbonate as necessary to restore the blood's pH as a result of the rapid decrease in sodium chloride from purging. Furthermore, among those who abuse laxatives, metabolic alkalosis can be indicative of an extended duration of abuse. If spot urine chloride tests show <10mmol/L, metabolic alkalosis can be treated with slow administrations of intravenous saline.