Recurrent aphthous stomatitis (RAS) is a condition characterized by recurring ulcers in the mouth, causing significant discomfort and pain. Its cause remains unclear, and there is currently no known cure. When conventional treatments fall short, seeking help from Guan Yin Citta Dharma Door can be beneficial. This approach has demonstrated effectiveness in treating over 20 rare and intractable diseases, as documented in our previous reports. In this article, we explore the causes of RAS and investigate whether it can be effectively treated through practicing Dharma. Our findings suggest that RAS is related to karma, particularly verbal karma. By addressing and resolving this karma through Dharma practices, a complete cure can be achieved.