The reliability of a short-term test for hepatocarcinogenesis induced by aflatoxin B1 (AFB1) was tested by comparing the early appearance of gamma-glutamyl transpeptidase (GGT)-positive foci with the occurrence of primary liver cancer at a later stage. All rats received a basic short-term treatment with AFB1 intraperitoneally, during which three experimental groups received Chinese green tea or 2000 or 5000 ppm butylated hydroxyanisole in the diet and a control group received basic diet. Some of the rats in each group were sacrificed at the end of the short-term procedure, and the remainder were observed up to 92 weeks. The livers of all animals were examined for GGT-positive foci or primary liver tumours. The GGT-positive foci were most numerous and largest and the incidence of liver tumours was highest in the control group. These findings suggest that GGT-positive foci are a valuable preneoplastic marker for AFB1-induced hepatocarcinogenesis, that the short-term model is fairly reliable, and that both Chinese green tea and butylated hydroxyanisole inhibit AFB1-induced hepatocarcinogenesis.