Forty-eight 154-d-old White Leghorn hens were fed a diet containing 0 (control), 0.5, 1.0 and 1.5% bamboo charcoal powder including vinegar liquid (SB). Compared with the control group, production performance in the SB groups did not differ. Egg production tended to be increased in the 0.5 and 1.0% SB groups, but decreased in the 1.5% SB group; the former two groups were higher than the latter (P<0.05). The SB groups showed a lower level of faecal ammonia gas and a higher level of polyphenol in the egg yolk, but the differences were not statistically significant. The intestinal villus height, cell area, and cell mitosis number tended to be higher in the SB groups. Duodenal cell mitosis was increased in all SB groups (P<0.05). The control group showed flat cells on the villus apical surface, while the SB groups showed protuberated cells. The present results indicate stimulating effects of dietary SB on intestinal villi and structure of epithelial cells and the 0.5 and 1.0% levels improved production performance. These suggest that the SB can be supplemented until a level of 1.0%.