Prevotella is a genus of anaerobic Gram-negative bacteria of the Bacteroidetes phylum, which also includes the clinically important genera Bacteroides and Porphyromonas. Prevotella strains are classically considered commensal bacteria due to their extensive presence in the healthy human body and their rare involvement in infections. Prevotella spp. are members of the oral, vaginal, and gut microbiota and are often recovered from anaerobic infections of the respiratory tract. Prevotella spp. predominate in periodontal disease and periodontal abscesses. Regarding Prevotella, studies focused on the associations between the diverse species, genome and habitats with dietary patterns, health and disease. Evidence revealed beneficial effects of some Prevotella strains in the gut such as improving CVD risk factor profile and glucose metabolism. Most studies reported that vegetarians harbour higher numbers of Prevotella species as well as a high Prevotella/Bacteroides ratio compared with non-vegetarians; omnivores. Nevertheless, there is a need for more studies in humans to ascertain a causal and potential disease-triggering role for Prevotella and more in-depth metagenomic studies are needed in order to reveal the health- or disease-modulating properties.