The Panel on Food Additives and Nutrient Sources added to Food (ANS) delivers an opinion re-evaluating the safety of butylated hydroxytoluene (BHT) (E 321). BHT is an authorised synthetic antioxidant that was previously evaluated by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the latest in 1996 and the EU Scientific Committee for Food (SCF) in 1987. The SCF established an ADI of 0-0.05 mg/kg bw/day based on thyroid, reproduction and haematological effects in the rat. JECFA allocated an ADI of 0-0.3 mg/kg bw/day for BHT based on effects in the reproduction segments and hepatic enzyme induction seen in two separate 2-generation studies in rats. The Panel concluded that BHT is not of concern with respect to genotoxicity and that any carcinogenicity would be thresholded. After the last SCF evaluation, two new 2-generation studies have been reported which were the basis for the ADI set by JECFA. Both studies revealed a NOAEL of 25 mg/kg bw/day. Overall, the Panel concluded that the present database gives reason to revise the ADI of 0.05 mg/kg bw/day. Based on the NOAEL of 25 mg/kg bw/day and an uncertainty factor of 100, the Panel derived an ADI of 0.25 mg/kg bw/day. Since the NOAEL of 25 mg/kg bw/day is below the BMDL10 value of 247 mg/kg bw/day derived from the data for the incidence of hepatocellular carcinomas in male rats, the Panel concluded that this NOAEL also covers the hepatocellular carcinomas observed in the long-term studies with BHT. Exposure of adults to BHT is unlikely to exceed the newly derived ADI at the mean and at the 95th percentile. For exposure of children to BHT from its use as food additive, the Panel noted that it is also unlikely that this ADI is exceeded at the mean, but is exceeded for some European countries (Finland, The Netherlands) at the 95th percentile.