AimsThis study evaluated the efficacy of a probiotic containing Bacillus toyonensis spores (Toyocerin((R))) in postweaning piglets against enteric pathogens. Methods and ResultsSeven hundred and ninety-two healthy weaning pigs of a commercial farrow-to-finish pig farm were used. The negative control group fed without Toyocerin((R)) and two experimental groups fed similar to the negative control group, but supplemented with Toyocerin((R)) at t 500mgkg(-1) diet (Toyocerin 500 group) and 1000mgkg(-1) diet (Toyocerin 1000 group), respectively. No significant difference (P>005) in morbidity and mortality rate between groups was noticed. The Toyocerin groups showed higher body weight (P<005) and lower feed conversion ratio compared to the negative control group. Diarrhoea score was less in both Toyocerin groups than negative control group (P<005). Moreover, the use of Toyocerin((R)) at 1000mgkg(-1) diet resulted in higher average daily feed intake compared to other groups (P<005), reduction of some enteric pathogens and increase of the number of lactic acid bacteria. ConclusionsThe use of Toyocerin((R)) in weaning pigs, especially at 1000mgkg(-1) diet, improved their health and growth performance. Significance and Impact of the StudyThis study shows that a feed additive containing B.toyonensis (Toyocerin((R))) protects against enteric pathogens in postweaning piglets when fed this additive at a proper dose. The use of Toyocerin((R)) at 1000mgkg(-1) diet resulted in higher average daily feed intake, decrease of some enteric pathogens and higher number of lactic acid bacteria. The effect of the probiotic in other age groups remains to be established.