Abstract: Objective: To analyze the oral clinical and hematological features related to vitamin B12 deficiency for early diagnosis and treatment. Methods: The main symptoms, clinical signs, past medical history, blood routine, and serum vitamin B12 and folic acid levels of 16 patients with vitamin B12 deficiency from January 2021 to November 2023 were retrospectively analyzed. Results: The main complaints of vitamin B12 deficiency patients were oral irritation pain, burning sensation, and oral ulcer. Clinical examination mainly showed erythema of oral mucosa and multiple small oral ulcers. Patients with a history of gastrectomy were more likely to develop anemia, and vitamin B12 deficiency in patients without a history of gastrectomy predated changes in hematology. Conclusion: Patients with special populations should be alert to the possibility of vitamin B12 deficiency if they have multiple recurrent oral ulcers, atrophic glossitis, mucous congestion erythema, and other lesions. It is recommended to further check the serum vitamin B12 level for early detection, diagnosis, and treatment of the disease.

Key words: vitamin B12 deficiency, oral clinical manifestations, serological test