From the ethanolic extract of the leaves of Alchornea cordifolia (Schumach. and Thonn.) Mull. Arg,, 5–methyl 4’ -propenoxy anthocyanidines 7-O-β-D – diglucopyranoside was isolated. The structure was elucidated using NMR spectroscopy in combination with IR and MS spectral data. Antibacterial studies showed that the isolated compound successfully inhibited Pseudomonas aerguinosa, Escherichia coli, Proteus mirabilis, Klebsiella pueumonia and Staphylococcus aureus. This result authenticates the use of the plant in phytomedicine for disease prevention and treatment of infections.