A new biotransformation product, steviol 19-β-gentiobiosyl ester, together with steviol 19-β-glucopyranosyl ester and steviol-13- O-β-glucopyranoside 19-β-glucopyranosyl ester (rubusoside), was isolated from Eucalyptus perriniana jar fermentor culture following the administration of steviol. Only rubusoside was isolated as a biotransforination product of steviol from Coffea arabica cell suspension culture.