Abstract
Azo-2-naphthol and 2-naphthol were tested against five microorganisms: Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa and Streptococcus faecalis. 2-Naphthol was slightly active while azo-2-naphthol was highly active against all the bacteria species tested. The presence of azo group contributed more than 60% of the antibacterial activities exhibited by azo-2-naphthol on all the bacteria tested.