Pathology of BHA- and BHT-induced lesions.

The pathology lesions from three studies, two with butylated hydroxyanisole (BHA) and one with butylated hydroxytoluene (BHT), are reviewed. When BHA was fed at 0.5 and 2.0% of the diet to F344 rats for two years, there was an increase in epithelial hyperplasia of the forestomach at both treatment levels. Papilloma and squamous-cell carcinoma of the forestomach were increased at the 2.0% level. When BHA was fed to beagle dogs at 1.0 and 1.3% of the diet for 180 days, no lesions/tumours of the distal oesophagus or stomach could be identified either at gross necropsy or by light or electron microscopy. The BHT was fed to Wistar rats at 0, 25, 100 and 250 mg/kg body weight. At the highest dose there was an increase in the number of rats with hepatocellular adenoma and with hepatocellular carcinoma.