Cogon grass Imperata cylindrica is a perennial grass belonging to the family Poaceae, and the rhizome-root portion of which is used for the treatment of bacterial infections, ringworms and other skin infections. Among the Mizo people they are directly consumed or juiced for the treatment of intestinal infection. Its chemical and biological properties are poorly documented. In this study, a methanol extract of the rhizome-root was prepared by hot extraction in a Soxhlet apparatus. Standard chemical tests were conducted. The presence of alkaloids, carbohydrates including reducing sugars, phytosterols, tannins, saponins and proteins were confirmed as the major bio-compounds. Free radical-scavenging activities were also determined. The plant extract indicated concentration-dependent scavenging activity on DPPH with an inhibitory concentration (IC50) of 2.14 µg/ml. H2O2 was similarly scavenged, in which the IC50 was 2.221 µg/ml. Our results suggest that I. cylindrica has important medicinal values.