Two experiments were conducted to determine the effects of dietary sodium butyrate on growth performance and response to Escherichia coli lipopolysaccharide (LPS) in weanling pigs. In the first experiment there was no effect of dietary sodium butyrate or tylosin on overall G:F, but there was a decreasing ADFI and ADG as levels increased. In the second experiment it was found that feeding diets containing sodium butyrate or carbadox did not alter ADG or ADFI compared with pigs fed the control diet. This indicates that dietary sodium butyrate does not enhance growth performance but may regulate the response to inflammatory stimuli in weanling pigs.