Carmine was fed continuously to male and female rats over three generations at dietary concentrations that provided intakes of 50, 150 or 500 mg carmine/kg body weight/day. In adult animals of all generations there were no effects of treatment on body-weight gain, food and water intakes or fertility. At autopsy the weights and the gross and microscopic appearance of the organs were normal. In the teratological investigations, examination of the foetal skeletons of the F3 generation revealed a slightly more advanced stage of ossification in all treated groups compared to those of the control. Survival, growth and development of offspring were similar in each group apart from a slight delay in the time of tooth eruption in the 150- and 500-mg/kg groups of the first and second generations. This was not seen in the final generation. It is concluded that carmine had no untoward effects on the growth and fertility of adult rats, or on the ante- and postnatal development of their offspring when given continuously at doses of up to 500 mg/kg body weight/day in the diet throughout all phases of mating, gestation, lactation, weaning and adult life over three successive generations.