This paper reports on the effects of a diet of vegetation contaminated by atmospheric fluorides upon the growth and age-accumulation of fluoride by a laboratory-maintained population of the short-tailed field vole, M. agrestis, a wild herbivore. Offspring of the voles fed the contaminated diet generally had lower growth rates and body weights during infancy and early adulthood than those fed a reference diet. The concentration and total fluoride burden of the femur were significantly higher in voles fed the contaminated diet. Following birth, the incisors of all offspring appeared normal, regardless of diet. Later, from approaching weaning onwards, the incisors of offspring weaned on to the contaminated diet showed marked morphological changes and severe dental lesions. Fluoride concentrations in the femur increased rapidly in late-suckling infants whose mothers were fed the contaminated diet, but appeared to reach an equilibrium concentration in adults which coincided with a slowing of the growth rate. Age is clearly an important influence upon the toxicology of fluoride because it affects the rate of accumulation by skeletal tissue.