ENVIRONMENTAL pollution by lead, resulting in part from the use of petrol additives, is well established, and lead is known to be transferred through food chains1. However, there has apparently been no previous long term study of the lead content of food. We have been able to make such a study by using samples of Danish food substances, which have been collected annually at the Health Physics Department of Risø National Laboratory. The samples are always dry ashed at 500 °C for 24 h and then stored in polyethylene boxes with close fitting lids. Tests show that this causes no loss of lead or contamination by lead. So far we have examined three cereals (spring and winter wheat (Triticum vulgare) and barley (Hordeurn sativum), and total diet2, which is the average daily diet of an adult in Denmark. (The composition of total diet is given in ref. 2.) We report here that there has been an overall decline in the lead content of these food substances between 1962 and 1976.