People living in far-flung areas of the world, especially ethnic tribal people practice traditional medicine as the first choice of disease treatment. The present study investigates the antioxidant, cytotoxicity, and anthelmintic activity of four medicinal plants traditionally used by tribal communities of Bodoland Region of Assam. Total phenolic and flavonoid content was estimated following spectrophotometry method. Antioxidant activity was measured by total antioxidant assay, FRAP, DPPH, ABTS, and TBARS assay. Antiproliferative and apoptosis-inducing activity of plants were carried out in DL cells. Cells were treated for 24 h with different doses of plant extracts. Furthermore, anthelmintic study was carried out by treating the helminth parasite at different doses of plant extracts. Phytochemical and antioxidant study showed rich TPC, TFC, and free radical scavenging activity in H. japonicum and H. sibthorpioides. Both the antiproliferative and anthelmintic activity showed a dose-dependent efficacy in all the plants. H. japonicum showed the strongest anthelmintic activity with LC 50 212.78 µg/mL followed by H. sibthorpioides (5.36 mg/mL), C. halicacabum (13.40 mg/mL), and A. scholaris (18.40 mg/mL). On the other hand, H. sibthorpioides showed stronger antiproliferative and apoptosis-inducing activity compared to other plants. The study observed a positive correlation between the antioxidant property and antiproliferative and anthelmintic activities of the plants. We, therefore, conclude that the secondary metabolites along with antioxidant molecules may have combined effects contributing the antiproliferative and anthelmintic activity of the plants.