Tagetes erectus (family: Asteraceae), commonly known as ‘African marigold’, is an ornamental plant widely distributed in India. The plant has been used in traditional medicines in India and elsewhere in the treatment of cold, bronchitis, rheumatism and inflammation. The flavonoid quercetin has been isolated from the methanol extract of the plant by column chromatography and identified by co-TLC, comparison of its melting point, UV, IR and NMR spectra. Quercetin content has been estimated as 1.22 (±0.26) % in the methanol extract of Tageteserectus whole plant based on HPTLC method using the solvent systemchloroform: methanol (8.5:1.5). The essential oil was isolated by hydrodistillation (oil yield 0.04% v/w) and 25 compounds comprising 93.9% of the constituents were identified by GC-MS analysis. Monoterpenoids Predominated the oil (78.5%), with piperitone as the major compound (40.1%) followed by terpinolene (12.7%) and limonene (12.0%). The in vitro antioxidant assays of the methanol extract showed moderate activity with IC50 values 109.45 (±1.22) μg/ml for DPPH radical scavenging assay and 201.53 (±4.48) μg/ml for superoxide scavenging assay and the marker compound quercetin showed IC50 values 26.40(±1.75) and 13.87 (±0.54) μg/ml respectively. Reducing power assay also showed moderate activity. Antibacterial activity of the methanol extract and the essential oil against gram positive and gram-negative bacteria were done using disc diffusion method. The essential oil showed remarkable activity against the tested organisms, while the extract showed only moderate activity.