Introduction: Recurrent aphthous stomatitis (RAS) is the most common ulcerative disease that affects the non-keratinized oral mucosa. The etiology is still unknown, but several local and systemic factors have been proposed as causal agents. Case description: three patients are reported with RAS associated with nutritional deficiencies, due to dietary restriction diets. The first case, a 19-year-old woman with iron deficiency, reported taking green tea daily and consuming a small amount of carbohydrates, fats and meat. The second case, a 32-year-old man with iron deficiency and vitamin B12 associated with vegan diet, although sometimes if he consumed meat. The third case, man of 50 years, vegan and ex-smoker for a year, presented deficiency of iron, vitamin B12 and folic acid. In all three cases a detailed questioning, clinical examination and complete blood analysis allowed to establish an adequate diagnosis, dental management and referral with a nutritionist, in order to treat the underlying pathology and not only provide a symptomatic treatment of the injuries. Discussion: In the setting of RAS, it is advisable to perform an analysis that includes a blood count, folic acid, iron and vitamin B12, to rule out possible systemic causes and eventually treat them. Clinical management aims to improve patient function and quality of life through topical and systemic therapies; however, it is essential to identify and control the causal factors that contribute; as well as, the exclusion or treatment of the underlying systemic disease.

Keywords: Recurrent aphthous stomatitis; Nutritional deficiencies; Vitamin B12; Folic acid; Iron; Treatment