Two cl1lde methanol and chloroform extracts obtained from leaves of Wifhallia sOllllliferarnand nine column fi'actions obtained from the cl1lde methanol extracts of leaves of WithaniarnsOll/nifera, water extracts of roots of Moringa stenopetala and leaves of Vernoniarnamygdalina were tested in vivo for antimalarial activity on Swiss albino male mice. Eachrnmouse in the study was infected interaperitonially with blood samples taken from micernpreviously infected with chloroquine sensitive PlasmodiulIl berghei that was diluted so thatrn0.2 ml contained 106_107 infected erythrocytes. The extracts were given to the infected micerninteraperitonially stm1ing fi'om three hours following inoculation. Antimalarial activity wasrnevaluated by taking blood smears on day four. This study revealed that methanol extractrnobtained fi'om leaves of Withania somnifera suppressed parasitemia significantly both inrncrude form (43.2 % at 750 mg/kg and 53.34 % at 900 mg/kg) and in fractionation of therncrude extract (FJw, 44.3 % at 200 mg/kg and 57 % at 300 mg/kg respectively). Columnrnfractions obtained from water extract of leaves of Vernonia alllygdalina also showedrnsignificant suppressive effect on the parasitemia level (F2v, 56.8 % at 200 mg/kg and 66.13 %rnat 300 mg/kg respectively). On the other hand column fractions obtained fi'om water extractsrnof roots of Moringa stenopetala did not show significant effect on parasitemia as comparedrnto the reported activity in its cl1lde fonn.rnKey words: Antimalarial activity, in vivo, Medicinal plants, Morillga stenopetala,rnPlasmodiulII berghei, Vernonia amygdalin a Withallia somllifera.