In the past we have reported successfully treating three patients suffering from RAS with Vitamin B12 (17). We also have data regarding the treatment of 15 RAS patients. (This data has not yet been published.) The frequency of sores in this group had been an average of 1.5 episodes per month before treatment with Vitamin B12. During treatment the frequency decreased to 0.1 episode per month. As far as we know, there is no research using a double-blind design that investigated Vitamin B12 treatment of patients suffering from RAS.