AbstractVitamins are organic compounds present in low concentrations in food, performing vital and specific cell metabolism functions. Vitamin B12 is essential for red blood cell formation in the bone marrow and its deficiency is caused, mainly, by gastrointestinal malabsorption. In addition to systemic manifestations, oral signs and symptoms have also been associated to this condition such as glossitis, papillary atrophy, painful erythema areas, burning sensation, dysgeusia, lingual paresthesia and itching. This study aims to report four cases of oral manifestations caused by vitamin B12 deficiency. All patients presented oral mucosa lesions. Vitamin B12 deficiency was diagnosed based in clinical characteristics and complementary exams. Oral supplementation for vitamin B12 deficiency was conducted/realized in three patients, while one patient was treated with parenteral doses. All of them showed partial or total remission of the signs and symptoms.