Numerous essential oils (EO) have broad spectrum antibacterial effect against microorganisms e.g. bacteria n fungi. Some common constituents that can be derived from EO include aldehyde, phenols, ketones, alcohol, terpenes, esters, ethers and other minor compounds. The antibacterial effect was reported more efficient when the aldehyde, rather than alcohol, form the dominant constituents of the EO. Although the mechanism of antibacterial is poorly understood but the disruption of the bacterial cell membrane is conceivable particularly for phenolics and terpenes-containing EO. This disruptive characteristics which is selective to bacterial cell wall is especially important for it signals a targeting potential by this mode leading to reduction in occurance of bacterial resistance. It is thus imperative to delineate structure of the presence aldehyde at molecular level and perhaps comforming it againts its activity at the site of action (so-called structure-activity relationship)….tbc