Urolithiasis is a worldwide problem which appears to be aggravated by the high-dairy-produce, highly energy-rich and low-fibre diets consumed in most industrialised countries. Together these factors lead to urine with a high risk of calcium oxalate and uric acid crystalluria. Epidemiological evidence points, in particular, to a high-meat protein intake as being the dominant factor within this combination. Such a diet not only increases the risk of stones in the population as a whole through its general effect on the urinary risk factors for stones but also may select out certain individuals who are metabolically more sensitive to this dietary stimulus and who show an exaggerated biochemical response to it. On the basis of epidemiological and biochemical studies, a move towards a more vegetarian, less energy-rich diet would be predicted to reduce the risk of stone formation in the population.