Safety and efficacy evaluation of drugs that could be used in SEP and SIRS should be associated with successful modeling of the disease state in animals. SEP and SIRS are clinical syndromes, produced in severe infections by microorganisms or trauma, pancreatitis, and burns. Sepsis accompanied by hypotension usually results in shock. The host's inflammatory response to infection, such as release of cytokines, is known to contribute to septic shock development. Two commonly used animal models in evaluating potential agents for SEP and SIRS are: aâ. Endotoxin (LPS) Challenge Model - infusion of LPS in animals. bâ. Focal Infection or Chronic Infection Model - infusion of live organisms, fecal material in the peritoneal cavity, infected material into soft tissue, and cecal ligation and perforation model. Data have shown that rodents and other animal species are generally resistant to endotoxin shock; exact features of sepsis in man have not been reproduced in animal models. In infection associated with bacteremia and other physiological changes, results are difficult to reproduce and some rat models show little systemic response and low mortalities. Antibodies raised against core region of LPS have failed to protect against SIRS whereas, when raised against O-side chain of LPS, they have been be protective in some animal models.