The current study was carried out to evaluate the anthelmintic efficacy of crude methanolic extracts of leaves of Croton macrostachyus and Nicotiana tabacum and rhizome parts of Zingiber officinale on nematode parasite, Haemonchus contortus. For these objectives, adult worm mortality assay (AWMA) was conducted on adult H. contortus to investigate the in vitro adulticidal effect of crude extracts from March to October 2021 G.C. The percentage yield of crude 99.9% methanolic extracts was 53%, 78%, and 44% for C. macrostachyus, N. tabacum, and Z. officinale, respectively. Phytochemical analysis using standard techniques was also used to detect secondary metabolites contained in the plants. The study revealed the presence of secondary metabolites such as tannins, flavonoids, steroids, and terpenoids in all extracts, which are considered to be the chemical components that are responsible for the wide therapeutic activities of several medicinal plants. In in vitro study, four graded concentrations of the crude extracts (500 mg/ml, 250 mg/ml, 125 mg/ml, and 62.5 mg/ml) were tested at regular time intervals, and parasite viability for 8 hours was recorded in triplicate. Albendazole (1.25 mg/ml) and distilled water were used as the positive and negative controls, respectively. At 4 hr posttreatment, the 62.5 mg/ml, 125 mg/ml, and 250 mg/ml concentrations of C. macrostachyus, N. tabacum, and Z. officinale extracts have caused significantly higher mortality (