A novel stilbene glycoside [piceid-(1-->6)-beta-d-glucopyranoside; PBG] from Parthenocissus tricuspidata was tested in vivo against Plasmodium berghei. PBG exhibited significant blood schizontocidal activity in a 4-day early infection, a repository evaluation, and an established infection, with a significant mean survival time comparable to that obtained with the standard drug, chloroquine (5 mg x kg(-1) x day(-1)).