Recent studies show than immune dysfunction dose have an important effect on the occurrence and development of sepsis. When the body suffer from the pathogenic microorganism attacking and sepsis, it activate the systemic inflammatory response (SIRS) and compensatory anti-inflammatory response syndrome (CARS). When it is out of balance between SIRS and CARS, the inflammatory response, immune paralysis or immune dysfunction occurs and the mixed anti-inflammatory response syndrome (MARS) exists, and then the multiple organ dysfunction. So, immune dysfunction is thought to be the key factors on the development of the sepsis. Some studies show that the sedation drug such as midazolam, propofol, dexmedetomidine could suppress the inflammatory response effectively and then modulate the immune function.