BACKGROUND AND OBJECTIVES: The use of Oral Nutritional Supplements (ONS) is widespread among patients with long- and short-term medical conditions. Although ONS serve an important purpose in the management of malnutrition, their effect on the oral hard and soft tissues is not well understood. The aim of this article is to conduct an analysis of the available literature relating to ONS and their impact on the oral environment. METHODS: This study was conducted following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines adapted by Liberati. The PICO question is as follows: Population: Individuals (both children and adults) Intervention: Use of Oral Nutritional Supplements Comparison: Individuals not taking Oral Nutritional Supplements Outcome: Increased risk of oral disease (specifically dental caries, periodontal disease or candida) The research question was “Are people who take ONS at higher risk of oral diseases than the general population?” Eligibility criteria The results obtained from the literature search were filtered, according to these inclusion and exclusion criteria: Inclusion criteria • Individuals were prescribed Oral Nutritional Supplements • All studies were included, including, case– control, cohort, cross-sectional or case studies. • Studies were included if they directly compared the association between ONS and oral health i.e. Effect of ONS on the oral environment had to be one of the aims of the study • Studies on human subjects or in vitro experiments • Published in English language • Studies from 1960 to the present day Exclusion criteria • Studies not in English • Review articles and case series were excluded • Studies including the use of other nutritional supplements such as vitamin or herbal supplements were not included. • Other supplemental feeding methods such as enteral or parenteral feeding were not examined 4 databases were searched: Medline (via Ebsco), Embase, Web of Science Core Collection, Google Scholar. Risk of bias was assessed using the ROBINS-I tool. RESULTS: A total of 58 records were identified through databases and searching bibliographies. 50 publications were excluded from the review, based on study title and abstract. The full text of eight articles were assessed for eligibility. No article answered the primary aim of the systematic review. Three articles discussed the secondary aim of the systematic review and these were included in the qualitative systematic review. The main outcome of the first study showed that the ONS had higher cariogenic potential than milk due to it’s higher acidogenicity. However, there was no statistical difference in dentine demineralisation and no significant difference in viable micro-organisms present. The main outcome of the second study showed that Escherichia coli, Staphylococcus aureus and C. albicans all grew at room temperature in the dairy-based ONS collected, and that C. albicans also grew in the juice which was milk protein-free and lipid-free. The third study showed that ONS were “potentially cariogenic” on enamel. DISCUSSION: Two studies were deemed as being at “low” of bias, however another study was deemed to be at “serious” level of bias. All studies stressed the possibility of dental disease caused by oral nutritional supplements, however there is not enough research available to imply causation. Due to the high sugar content of these supplements, and the known dental implications of this, it would be beneficial to carry out more research into this area.