The following study was undertaken to determine whether dietary supplementation with glutamine can be used to modulate the immune response following challenge with methicillin-resistant Staphylococcus aureus (MRSA) organisms in mice. Thirty BALB/c female mice were randomized into 3 groups: group A (n = 10) were fed 20% casein diet (control), whereas the mice in Groups B (n = 10) and C (n = 10) were given 20% casein diet supplemented with 2 and 4% glutamine, respectively. The diets were made isonitrogenous by glycine and alanine supplementation. On the 10th day on these treatments, each mouse was challenged intravenously with 2 x 10(8) colony-forming units (CFU)/ml of MRSA organisms and mortality was noted for 20 days. The survival rate in Group A (20%) tended to be lower than the rates in Group B (40%), and Group C (70%). CFU values of spleen and kidney of the surviving mice 20 days post challenge were not different among the three groups (p < 0.05). The present results suggest that dietary glutamine supplementation may be effective as a nutritional immunomodulator for the recovery from MRSA infection.