Design: This was a randomised, double-blind, placebo-controlled trial.
Intervention: One tablet was taken each day before sleep for 6 months. The test group received sublingual vitamin B12 tablets (1000 mcg of vitamin B12) whereas the control group took a placebo of the same shape, size, colour and flavour. Participants met with staff monthly.
Outcome measure: Duration (days) of an aphthous stomatitis episode, monthly number of aphthous ulcers, and severity of pain according to the Numerous Rating Scale (NRS), were recorded in a diary.
Results: Fifty-eight people suffering from recurrent aphthous stomatitis (RAS) participated: 31 were allocated to the intervention group and 27 to the control group. The duration of outbreaks, the number of ulcers, and the level of pain were reduced significantly (P <0.05) at 5 and 6 months of treatment with vitamin B12, regardless of initial vitamin B12 levels in the blood. During the last month of treatment a significant number of participants in the intervention group reached "no aphthous ulcers status" (74.1% vs 32.0%; P <0.01).
Conclusions: Vitamin B12 treatment, which is simple, inexpensive and low-risk, seems to be effective for patients suffering from RAS, regardless of the serum vitamin B12 level.