AbstractBACKGROUNDMany strategies, such as the antibiotic growth promoters, have been developed to improve intestinal health and performance of newly weaned piglets. Natural products such as essential oils have been scientifically recognized as growth enhancer feed additives for weanling pigs, replacing the antibiotics. Therefore, it has been hypothesized that Brazilian red pepper could replace performance‐enhancing antibiotics also in weanling pig diets. However, one experiment was conducted to determine the effects of dietary Brazilian red pepper essential oil or antimicrobial growth promoter on intestinal health and growth performance of weanling pigs.RESULTSNo effects of treatments were observed on performance and organ weights (P > 0.05). Overall, both additives [red pepper essential oil (RPEO) or antibiotic (ANT)] increased gut Lactobacillus counts compared to negative control, as well as reduced villi density (P < 0.05). Animals fed diets containing 1.5 g kg−1 RPEO presented the lowest incidence of diarrhea (P < 0.05).CONCLUSIONOur findings suggested that essential oil from Brazilian red pepper or chlorohydroxyquinoline added in weanling pig diets affect gut microbiota and histology without affecting performance and organ weights. In addition, there was an indication that high doses of essential oil could reduce the incidence of diarrhea. © 2017 Society of Chemical Industry