Abstract: In this study,60 pure bred mice were divided into three groups 20 each:(1) AFB1 infected group,(2) AFB1 plus tobacco smoking group and (3) Control group.Crystalline AFB1 was dissolved in DMSO and fed the experimental mice.An affinity purifed polyclonal rabbit antiserum to human bFGF was used as primary antibody with immunohistochecal staining,bFGF was frequently detected in the cytoplasm of AFB11 infected group.The expression intensities were shown as follows:AFB1 infected groupcontrol and AFB1 plus tobacco smoking group.The results showed the expression of bFGF demonstracted a close correlation to the degree of malignancy.The bFGF expression in each group showed positive correlation with nuclear DNAcontent.So we proposed that cigarette smoking might be protected against AFB1 induced primary cancer of the liver in mice.