Recurrent aphthous stomatitis is a common disease of the oral mucosa, affecting 20 per cent of the general population.1 However, the aetiology of this disease is unknown. This is the first controlled study to compare zinc levels in recurrent aphthous stomatitis patients with those of a well-matched, healthy, control population.

Twenty-five patients with a history of recurrent aphthous stomatitis and 25 healthy people (control group) took part in the study. Patients aged between 20 and 40 years with recurrent oral aphthous ulcers less than 1 cm in diameter were included. Exclusion criteria were pregnancy and lactation, systemic disease (ulcerative colitis, Crohn's disease, Behçet's disease), any current medication (topical or systemic), dental surgery during the previous month and deficiencies in iron, folic acid or vitamin B1, B2, B6 or B12. Serum zinc levels were compared between patient and control groups.

Zinc deficiency was detected in 28 per cent of recurrent aphthous stomatitis patients and in 4 per cent of controls. The mean serum zinc level in the patient group was significantly lower than in the control group.

These results suggest an association between zinc deficiency and recurrent aphthous stomatitis.