Antimicrobial activity of oil from alligator pepper (Aframomum melegueta) was tested against five pathogenic organisms, Klebsiella pneumonia, Salmonella typhi., Bacillus cereus, Escherichia coli and Staphylococcus aureus. The zone of inhibition of K. pneumonia was found to be 0.90 ± 0.01 mm, E. coli 0.70 ± 0.01 mm, S. typhii 0.60 ± 0.01 mm, B. cereus 0.04 ± 0.02 mm and Staphylococcus sp., 0.80 ± 0.02 mm. The oil was found to have more effect on Klebsiella pneumonia, followed by Staph. aureus, E. coli, S. typhii and B. cereus in descending order. These results show that the oil can effectively eliminate K. pneumonia and Staph aureus from human system if effectively administered in appropriate proportion.The physical characteristics are: %yield is 16.3522 ± 0.01%, specific gravity is 0.9051 ± 0.01, refractive index is 1.3335 ± 0.01, viscosity is 0.2327 ± 0.02 and colour is deep-yellow.