Very low concentrations were measured for MMP-8: 0.80 (0.00–1.99) ng/ml in plasma and 0.00 (0.00–0.30) ng/ml in PF in the group negative for sepsis, 1.60 (0.45–2.40) ng/ml in plasma and 0.29 (0.00–0.75) ng/ml in PF in the questionable group, and 1.79 (0.00–5.47) ng/ml in plasma and 0.05 (0.00–1.85) ng/ml in PF in horses tested positive for sepsis. This evidence concerns the gene MMP8 and Sepsis.