abstract–A study of enamel fluorosis in 1,094 children was carried out in areas with a water fluoride content of from<0.2 mg/1 with and without supplementary fluoride, to 2.75 mg/l. The fluorosis was correlated with different infant diets and also with the calculated supply per kilo body weight. As in cattle, 0.1 mg F/kg body weight daily appears to cause fluorosis. This dose may for example be reached with water‐diluted gruel powder in low‐weight infants with high consumption in low F areas, in normal weight infants in 0.8 areas, and also in high‐weight infants in 1.2–1.5 areas. The resultant fluorosis is very mild or mild and not disfiguring. Enamel fluorosis can be avoided or minimized in areas with up to at least 1.2 mgF/1 water if F‐supply, e.g. water‐diluted gruel and/or supplementary fluoride, is not commenced until 6 months of age when body weight is higher. With a water fluoride content of 2.75 mg F/l a very mild fluorosis is difficult to avoid also with normal water consumption during the 1st