Two oligosaccharides, a heptasaccharide (HS) and an octasaccharide (OS), isolated from Paris polyphylla var. yunnanensis, stimulated the growth and saponin accumulation of Panax ginseng hairy roots at 5-30 mg l(-1). HS and OS at 30 mg l(-1), fed separately to hairy root cultures at 10 days post-inoculation, increased the root biomass dry weight by more than 70% to -20 g l(-1) from 13 g l(-1) and the total saponin content of roots by more than 1-fold to -3.5% from 1.6% (w/w). The results suggest that the two oligosaccharides may have plant growth-regulatory activity in plant tissue cultures.