It has recently been found that patients suffering active Crohn's disease have significantly less recoverable bifidobacteria in their faeces compared to healthy individuals. This reduction in bifidobacteria numbers was observed to be directly correlated with decreased levels of B-D-galactosidase production and activity (Favier C et al. Dig Dis Sci 1997;42:817-822). B-D-galactosidase is an enzyme produced by bifidobacteria. These results support suggestions proposed in other studies (Bartram HP et al. Am J Clin Nutr 1994;59:428-432) that strains of bifidobacteria may play important roles in maintaining a balanced healthy intestinal microflora.