Abstract: The present study evaluated antimicrobial efficacy of essential oil and in vitro antioxidant activities of the aqueous extract from Colubrina asiatica (L.) Brong. as well as the chemical composition of essential oil. In the present investigation, Colubrina Water Extract (CWE) was studied for its antioxidant activity and Colubrina Essential Oil (CEO) for anti microbial properties. The antioxidant properties of CWE were evaluated using different free radical scavenging assays, such as reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging and metal chelating activities. We found that CWE had powerful antioxidant activity. The different concentrations (50, 100 and 250 g) of CWE showed 39, 66 and 98% inhibition on peroxidation of linoleic acid emulsion, respectively, while 60 g mL–1 of ascorbic acid, exhibited only 30% inhibition. Moreover, CWE had effective reducing power, free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging and metal chelating activities at the same concentrations. Those various antioxidant activities were compared to standard antioxidants such as ascorbic acid, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), gallic acid and quercetin. In addition, total phenolic compounds in the CWE were determined as Gallic acid equivalent. The Colubrina Essential Oil (CEO) content quantified showed presence of 10 compounds in which, dodecamethylcyclohexasiloxane has showed the highest (17%) and dehydro-N-[4,5-methylenedioxy-2-nitrobenzylidene]-tyramine showed the lowest percentage (1.9%). Cubebene, comprised of 14%. The antimicrobial activity of oil was studied on gram negative and gram positive bacterial.