Because urine is the main vehicle for excretion of fluoride, analysis of 24 hour urine excretion is presently the best marker of fluoride intake (3). Recording of fluoride excretion in urine over 24 hours has been recommended before and after introduction of fluoride- based community preventive programmes. A WHO document, published in 1999, offers detailed guidelines for the method and calculations: based on these, the optimal fluoride concentration in milk and the appropriate intake of fluoride can be determined.