Sodium Chloride BP 1973. Common salt, NA CI, a compound widely distributed in nature and essential in the diet. A 0.9 per cent solution is used for perfusions and irrigations (physiological saline). Excess loss of sodium chloride from the body due to excessive sweating causes heat cramps which are relieved by drinking weat salt solution. Hypertonic solutions are used as fomentations; large quantities of saline by mouth, particulary hypertonic, irritate the gastro-intestinal tract causing nausea and vomiting.