Our results showed that FGF21 treatment after liver injury could upregulate the expression of superoxide dismutase (SOD) and downregulate the expression of malondialdehyde (MDA), catalase (CAT), acute suppurative thyroiditis (AST), and alanine aminotransferase (ALT); it also effectively inhibited apoptosis of damaged liver cells, upregulated the expression of the anti-apoptotic gene bcl2, and downregulated the expression of apoptosis genes bax and p53; the expression of autophagy marker protein LC3B was also upregulated. This evidence concerns the gene CAT and suppurative thyroiditis.