(Z)-3-(chloromethylene)-6-methylthiochroman-4-one (CMMT) is a new thiochroman ketone compound. Earlier assessments have verified its probable activation on immunine system. We found that CMMT has lipopolysaccharide (LPS)-like effects in vitro and in vivo. The cultured RAW264.7 macrophages and isolated mice intraperitoneal macrophages were treated with different concentrations of CMMT and 800ng/ml lipopolysaccharide (LPS) respectively, and detected the amount of TNF-α, IL-6, NO in supernatant. CMMT and LPS were injected into the housed mice and detected the amount of TNF-α. The results showed that CMMT, like LPS, concentration-dependently stimulated production of TNF-α, IL-6 and NO.