current study was formulated to analyze the chemical composition, pharmacological activities, and toxicology study of chromolaena odorata aerial part essential oil (coeo) grown in north east india. gas chromatography/mass spectroscopy was used for chemical composition analysis. the antioxidative potential was tested using dpph and reducing power assays. protein denaturation and protease inhibitor assays for anti-inflammatory activity and allium cepa assay were used to test the genotoxicity of the essential oil. standard disc diffusion and minimum inhibitory assays (mic) were employed to test the antimicrobial efficacy of coeo and acetylcholinesterase (ache) inhibitory assay was used for anticholinesterase activity. gc/ms analysis revealed geijerene (26.34 %), -copaene (17.87 %), caryophyllene (11.14 %), 3-carene (10.63 %), cadinene (7.98 %), cyclohexane, 1-methylene-4-(1-methylethenyl)-(3.37 %), elemol (2.89 %), -muurolol (2.77 %), as major components. standard dpph, protein denaturation, and protease inhibitor assays revealed (ic50= 15.88 g/ml, 19.35 g/ml, and 27.28 g/ml respectively) strong antioxidant, anti-inflammatory potential of coeo. allium cepa assay showed negative genotoxicity with (mitotic index) mi=16.38 %, which is close to distilled water mi=19.20 %. while disc diffusion assay (zone of inhibition for b.cereus 16.56 +/- 0.002 mm; s. aureus 14.20 +/- 0.057 mm; s. cerevisiae 10.67 +/- 0.015 mm; a. fumigatus 10.15 +/- 0.05 mm) and mic (b. subtilis, s. aureus 2.50 l/ml), showed the antimicrobial potential of coeo. strong ache inhibitory activity was observed with an ic50 value of 61.98 g/ml. from all the results obtained it is clear that coeo could be used for future research, development, and in preparation of cost-effective pharmacologically important herbal drugs after proper validations.