Plants have been used since ancient times to cure diseases and to improve health and wellbeing of the populations. Plant diversity is a great source of medicines, while it provides direct economic benefits in the form of timber, food, fibre, industrial enzymes, flavours, cosmetics, emulsifiers, dyes, plant growth regulators, bio-pesticides and biofertilizers etc. The secondary metabolites, alkaloids, saponins, quinones, indoles, anthraquinones, terpenoids, flavonoids, phenolic compounds and amino acids are localised in cells. These have therapeutic properties and responsible for phytochemical markers to identify the genuine drug. Strychnos colubrina L. was screened for the presence of secondary metabolites using standard protocols as given by Harborne (1973),Gibbs(1974), Kokate (2001)and Khandelwal (2006), followed by pharmacological evaluation. Methanolic leaf extracts are tested for antioxidant and antimicrobial activities. The results were expressed as standard ± mean deviation (SD) of five replicates. Where ever applicable, the data were subjected to one-way and 2-way ANOVA and differences between samples were determined by with Scheffe’s post hoc test, Dunnet’s test using the program Statistical Analysis System (SASS V25). P Values < 0.05 were regarded as significant. In the preliminary phytochemical studies, the tannins, phenolic compounds, Alkaloids, flavonoids, Saponins, fats, oils, terpenoids have shown positive test in Strychnos colubrina. Glycosides, Lignins, Quinones, Anthraquinones, Anthocyanides, Coumarins, Carbohydrates, reducing sugars and Aminoacids are found to be absent. Sterols are absent in Strychnos colubrina. Administration of methanolic leaf extracts of Strychnos colubrine (200mg/kg) to have significant detrimental effect on one of 3 bacterial strains used i.e, Staphylococcus aureus and it has no effect on other 3 microbes namely, Bacillus subtilis, Pseudomonas aeruginosa and a fungal strain namely Candida albicans. Methanolic extract of plant leaves of Strychnos colubrina has not earlier been reported to have anti-microbial activity. The statistical analysis of the DPPH and NO3 free radical tests with the Strychnos colubrina methanol extract has shown significant difference in results with the control groups in both the comparisons. The extracts solution exhibited significant anti-oxidant properties in the both tests Present study is significant and fills the gap in the ethno-medico-botanical repository of Andhra Pradesh.