Hyperchloraemia can occur with excessive loss of bicarbonate due to gastrointestinal loss with prolonged vomiting or diarrhoea, sweating or dehydration. It can also occur with renal tubular acidosis, mineralocorticoid deficiency, compensated respiratory alkalosis from hyperventilation, diabetic ketoacidosis and methanol poisoning or salicylate toxicity. Hyperchloremia frequently coincides with hypernatraemia.

Hypochloraemia most commonly results from loss of body fluids from prolonged vomiting or chronic diarrhoea and in congestive heart failure. Low serum chloride levels are also seen in conditions associated with high serum bicarbonate concentrations such as chronic lung disease causing respiratory acidosis; or metabolic alkalosis. Low chloride occurs in Addisons disease.