Moringa oleifera, commonly known as the drumstick tree, has gained considerable scientific attention due to its rich phytochemical composition and diverse pharmacological properties. The plant contains multiple bioactive compounds, including polyphenols, flavonoids, isothiocyanates, glucosinolates, and alkaloids, which collectively contribute to its antioxidant, anti-inflammatory, anticancer, and antimicrobial activities. This review summarizes the major bioactive constituents of M. oleifera and highlights their mechanisms of action in relation to chronic disease prevention and health promotion.