- Recurrent aphthous stomatitis (RAS) is one of the most common oral mucosal lesions seen in primary care. Over the past four years we have treated 15 RAS patients with vitamin B12. Of these, 11 patients reported a rapid and complete recovery from RAS during treatment and the other four reported pronounced reduction in the frequency and severity of RAS episodes. We suppose that a treatment with vitamin B12 can be effective for patients suffering from RAS any origin, regardless of their serum vitamin B12 level. Now we are doing double-blind, placebo-controlled, randomized clinical trial addressing the issue. It's supposed to confirm the safety and effectiveness of vitamin B12 therapy for RAS.