The in vitro activity of different fractions of leaf extract of Anacardium occidentale (L.) (Cashew) on some bacterial isolates, namely, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa was investigated. Disc diffusion method was employed and the result showed sensitivity of the test organisms to different concentrations of chloroform, crude, methanol and ethyl acetate extract fractions. Highest zone of inhibition of 8mm was observed for E. coli at 2000 and 1000 μg/l of chloroform and ethyl acetate fractions respectively. Staph. aureus and P. aeruginosa were most sensitive to chloroform extract with zones of inhibition of 10 and 8.5mm respectively while the petroleum ether fraction showed no activity at any concentration on the test organisms.

Keywords: Antibacterial activity, Medicinal Plant, Extract