Background. Recurrent aphthous stomatitis, or RAS, is a common oral disorder of uncertain etiopathogenesis for which symptomatic therapy only is available. This article reviews the current data on the etiopathogenesis, diagnosis and management of RAS in a primary care setting. Methods. The authors reviewed publications on Medline from 1995 through 2000, the period since the last major reviews were published. Results. RAS may have an immunogenetic background owing to cross-reactivity with Streptococcus sanguis or heat shock protein. Predisposing factors seen in a minority include haematinic (iron, folate or vitamin B12) deficiency, stress, food allergies and HIV infection. While topical corticosteroids remain the mainstay for therapy, a number of other immunomodulatory modalities now are available. Conclusions. There is still no conclusive evidence relevant to the etiopathogenesis of RAS, and therefore therapy can attempt only to suppress symptoms rather than to address the basic issues of susceptibility and prevention. Clinical Implications. In the majority of patients, symptomatic relief of RAS can be achieved with topical corticosteroids alone, with other immunomodulatory topical agents or by combination therapy.