The oral cavity being the hub of gamut of microbes, promotes the establishment of distinct microbial communities, such as on the mucosa and teeth. Metabolism of these organisms facilitates the attachment and growth of the subsequent colonisers. A delicate balance is maintained in the microbial ecosystem, with these organisms contributing to normal development and defences. However, any change or disruption in the microbial profile due to either intrinsic or extrinsic factors can result in an unfavorable shift toward pathogenic organisms triggering various diseases like dental caries or periodontitis. Furthermore, recent findings also state that these microorganisms may lead to systemic diseases like diabetes or atherosclerosis. This article is an attempt to give an overview of the altered flora in diseased states.