Methods for treating sepsis are provided and include the administration an effective amount of cerium oxide nanoparticles to a subject in need thereof. The sepsis being treated can include polymicrobial sepsis and can include the administration of about 0.1 mg/kg to about 1.0 mg/kg of the cerium oxide nanoparticles. The administration of the cerium oxide nanoparticles further allows one or more of the symptoms of sepsis to be treated. Methods of treating an inflammatory disorder that make use of cerium oxide nanoparticles are further provided.