When polymicrobial sepsis was induced by CLP in mice, STAT3 activation occurred at 3 h, with maximal activation at 6–12 h, although the kinetics of STAT3 activation after CLP appeared to be somewhat different among tissues: STAT3 phosphorylation was observed to be long-lasting in lung tissues but to show a temporary rise in liver, heart, and kidney tissues. Here, STAT3 is linked to Sepsis.