Medicinal plants have been used as a source of medicine to alleviate diseases. Andrographis paniculata is one of the highly used potential medicinal plants in the world. This plant is traditionally used for the treatment of common cold, diarrhoea, fever due to several infective cause, jaundice, as a health tonic for the liver and cardiovascular health, and as an antioxidant. It is also used as a contraceptive. All parts of this plant are used to extract the active phytochemicals, but the compositions of phytoconstituents widely differ from one part to another and with place, season, and time of harvest. The aim of the study was to evaluate the Phytochemical analysis, antioxidant, antibacterial activities and GCMS analysis of stem extract of Andrographis paniculata. The Phytochemical analysis of A. paniculata reveals the presence of alkaloids, terpenoids, steroids, phenolic compounds, flavonoids, glycosides, tannins and saponins. Antioxidant assays such as DPPH• radical, superoxide radical, phosphomolybdenum reduction and Fe3+ reducing power assays were carried out for evaluating antioxidant activities. The maximum DPPH• radical scavenging activity of A. paniculata stem extract was 66.99±0.75% at 300 µg/mL concentration. The maximum superoxide radical scavenging activity of stem extract was 77.90±0.34% at 120 µg/mL concentration. The maximum Mo6+ (molybdenum) reduction of stem extract was 79.86±0.87% at 300 µg/mL concentration. The maximum Fe3+ reduction was 45.17±1.37% at 120 µg/mL concentration. The maximum α-amylase enzyme inhibition of stem extract of A. paniculata was 57.70 ±0.97% at 120 µg/mL concentration. The maximum hemolysis inhibition was 54.00±1.16 at 120 µg/mL concentration. Antibacterial activity was carried out by well diffusion method and the stem extract showed maximum zone of inhibition of 20 mm against Staphylococcus aureus at 500 µg/mL concentration.