Butylated hydroxytoluene (BHT) is a phenolic antioxidant. It has been shown to inhibit lipid peroxidation. It causes lung injury and promotes tumors in mice, but this may be due to a metabolite of BHT, 6-tert-butyl-2-[2′-(2′-hydroxymethyl)-propyl]-4-methylphenol. Metabolites of BHT have also been reported to induce DNA strand breaks and internucleosomal DNA fragmentation (a characteristic of apoptosis) in cultured cells. In rats, a single intraperitoneal injection of BHT (60 mg/kg body mass) results in a significant increase in nuclear DNA methyl transferase activity in the liver, kidneys, heart, spleen, brain and lungs. Incubation of alveolar macrophages with BHT significantly reduced the level of TNF-α which may explain the mechanism by which this antioxidant reduces inflammation. Preincubation of aspirin-treated platelets with BHT inhibits the secretion, aggregation, and protein phosphorylation induced by protein kinase C activators. BHT was also found to inhibit the initiation of hepatocarcinogenesis by aflatoxin B1.