The phytochemical investigation of an aqueous ethanolic extract of Galinsoga parviflora Cav. (Asteraceae) resulted in the isolation and identification of eleven compounds namely: triacontanol, phytol, beta-sitosterol, stigmasterol, 7-hydroxy-beta-sitosterol, 7-hydroxystigmasterol, beta-sitosterol-3-O-beta-D-glucoside, 3,4-dimethoxycinnamic acid, protocatechuic acid, fumaric acid, and uracil. Furthermore, 48 volatile constituents were identified in the hydrodistilled oil of the aerial parts. The ethanolic extract at a content of 400 mg/kg body weight (BW) exerted 87% reduction in the alanine aminotransferase enzyme level in cirrhotic rats compared with the standard silymarin (150 mg/kg BW) and also exerted a reduction in the blood glucose level equivalent to that of glibenclamide (5 mg/kg BW) in diabetic rats. The ethanolic extract, light petroleum and ethyl acetate fractions exhibited substantial antimicrobial activity against Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli, Aspergillus niger, and Candida albicans. The ethyl acetate fraction showed strong antioxidant activity at a concentration of 150 mg/mL as compared with 0.1 M ascorbic acid. The cytotoxic effect against the MCF-7 cell line was found to be weak.