Butylated hydroxyanisole (BHA) was given to pregnant SPF pigs (Danish Landrace) in doses of 0, 50, 200 and 400 mg/kg body weight/day from mating to day 110 of the gestation period. The BHA was mixed in the diet (pelleted). Caesarean section was performed on gestation day 110. BHA affected neither the reproduction data nor the incidence of defects in the foetuses. Significantly lower weight gain was observed in the group of dams on the highest dose. Absolute and relative organ weights for the liver and thyroid gland showed a dose-related increase. Proliferative and parakeratotic proliferative changes of the stratified epithelium of the stomach were found in both control and treated pigs. In addition, proliferative and parakeratotic changes of the oesophageal epithelium were observed in a few pigs in the two groups on the highest doses. Papillomas were not found, and no changes of the glandular part of the stomach were observed.