Acidic metabolites were precipitated from ethanolic extract of Garcinia kola seed and fractionated by column chromatography to obtain three fractions AM1, AM2, and AM3. Chemical test on the acidic metabolites and the fractions showed they were mainly flavonoids. In vitro antibacterial screening of the fractions showed they possessed antibacterial activity. They inhibited the growth of five human test bacterial isolates: Coliform bacilli, Escherichia coli, Salmonella spp., Staphylococcus aureus and Streptococcus spp. Their inhibition zone diameters ranged from 8 mm to 26 mm. The standard control antibiotic Ciprofloxacin gave inhibition zone diameters ranging from 18 mm to 20 mm, at the same concentration of 100 mg/ml for the same test bacteria. It was concluded that with appropriate standardization, the three fractions from the acidic metabolites of ethanolic extract of seed of Garcinia kola could effectively complement the existing antibiotics with beneficial health effect.