As the growth factor of lactic acid bacteria, LD (trehalose) was isolated from Lentinus edode5 by using silica gel column chromatography. LD induced the growth of Bifidobacteria breve and Lactobacillus brevis, which were isolated from human feces. LD selectively induced the growth of lactic acid bacteria among total microflora. When total intestinal microflora were cultured in the medium containing LD, it stimulated the growth of lactic acid bacteria and inhibited harmful enzymes, ${eta}$-glucosidase, ${eta}$-glucuronidase, and tryptophanase, of intestinal bacteria. LM, which was a monosaccharide from L. edooles, induced the growth of lactic acid bacteria but it seems to be invaluable in vivo. LH isolated from L. edodes by Sephadex G-100 column chromatography was not effective for the growth of lactic acid bacteria.