Interactions among infectious agents, nutrients and xenobiotics in which, xenobiotics and nutrients may affect host resistance to infection, as well as the microorganism virulence are a developing concern in food and environmental safety assessment. Nutrients and xenobiotics may induce either immunostimulative or immunosuppressive effects that may affect the host resistance and the course of the disease differently in different infections. This field has become a new avenue of research in food toxicology and food-borne diseases. For this purpose, some host resistance models in rodents are available but more are needed. Several microorganisms produce a clinically relevant disease useful for estimation of risk to man. Previously and currently used models include bacterial, viral and parasitic infections. The used microorganisms are either human pathogens adapted to experimental animals or unadapted human pathogens for which adequate animal models exist, where host resistance mechanisms and pathophysiological changes in animal and man are comparable. This report is a summary of effects of xenobiotics and nutrients on host resistance in presently used experimental human infections adapted to rodents.