[Oxaluria in urinary lithiasis]

The normal value of oxaluria, as determined by gasliquid chromatography, is about 30 mg/24 h. In most cases of renal stone formation (60-70%) the stones are composed of calcium oxalate alone or associated with calcium phosphate. The more evolutive the disease, the higher the oxaluria. The part played by oxaluria in renal stone formation and the need to include its determination in regular examinations of stone formers must be stressed. Treatment of hyperoxaluria is both medicinal and dietetic : control of oxalic acid-rich food intake and reduction of the intestinal absorption of oxalate caused by calcium-deprived diets. The diet must be completed by therapeutic measures aimed at reducing the oxaluria and increasing the urinary factors preventing crystallization.