In the current study, in vitro experiments were conducted to determine the possible anthelmintic effects of crude aqueous and hydro-alcoholic extracts of the seeds of Croton macrostachyus, Ekebergia capensis, Coriandrum sativum, Acacia nilotica, Terminalia schimperiana, Jatropha curcas, leaves of Lawsonia inermis, Chenopodium ambrosioides, ripe berries of Hedera helix, and bark of Albizia gummifera on eggs and adult Haemonchus contortus. Aqueous extracts of C. sativum and H. helix were also investigated for toxicity (LD50 determination) in Albino mice and for in vivo anthelmintic activity in sheep infected with H. contortus. Both extract types of C. macrostachyus, E. capensis, C. sativum, J. curcas, A. gummifera and aqueous extract of A. nilotica inhibited hatching of eggs at concentration less than or equal to 2 mg/ml. Based on their ED50, the six most potent extracts were aqueous extract of E. capensis (0.06mg/ml), Hydro-alcoholic extract of C. ambrosioides (0.09mg/ml), aqueous extract of C. macrostachyus and J. curcas (0.1mg/ml) aqueous extract of C. sativum and H. helix (0.12mg/ml), in decreasing order of potency. Hydro-alcoholic extract of A. nilotica, both extracts of T. schimperiana and L. inermis did not inhibit hatching of eggs of H. contortus significantly and in dose dependent manner at all concentrations tested. Hydro-alcoholic extracts of most of the plants have shown better in vitro activity against adult parasites compared to the aqueous extract. Hydro-alcoholic extracts of C. macrostachyus, A. gummifera, C. sativum and H. helix produced mortality of adult H. contortus significantly to the level of 90, 86.67,85 and 66.67% at concentration of 8 mg/ml while aqueous extracts produced only 36.67, 33.33, 45,and 29.17% respectively at the same concentration. Like their activity on eggs, extracts of A. nilotica, T. schimperiana, J. curcas and L. inermis have shown no statistically significant effect on survival of the adult parasites at the concentrations tested, and a few mortality cases recorded were not dose dependent (p