Chlorine is present in food and our body almost entirely in the form of chloride. Chloride is important in maintaining water balance, and is an essential component of gastric juice. We get our supplies of chlorine from food mainly in the form of sodium chloride (salt). Dietary deficiency of chlorine is rare and is only likely to occur if you have excessive losses from your body. This can result from prolonged vomiting, diarrhoea or profuse sweating. If you are on a severe sodium-restricted diet it may be necessary to obtain chlorine from other sources.