UMEÅ, Sweden: Recurrent aphthous stomatitis (RAS) is the most common painful oral mucosal disease in the world, occurring in 5%–25% of the world’s population. Swedish start-up Mucocort is among the vanguard of companies working to develop an effective treatment for RAS and has created an intra-oral patch that promises to significantly reduce pain and expedite healing. It recently received approval from the Swedish Medical Products Agency and the Swedish Ethical Review Authority to commence a clinical trial in August.