This research was aimed to study the knowledge of folk doctor for the treatment for Lah disease in the infant and toddler which focused on studying the treatment process for Lah disease, the treatment process for applying herbs and suggestion for after treatment. This research was qualitative research by paraphrasing the knowledge from folk doctor, Mr. Boonyong Sriutthakowit which the data was gathered from interviewing, then it was categorized and analyzed. The findings revealed that the traditional treatment was instructed from his father as he had observed which it was not the current medicine, and Mr. Boonyong Sriutthakowit was the expert for the treatment for Lah Disease. The treatment would start with asking the medical profile, checking the body, and applying herbs for sweeping on the tongue and buccal fat pad, then the ulcus was recovered after 1 – 5 times of this treatment which depended on its violence. Additionally, it was applied with the incantation by the creed that it would expedite the patients to get recover as physical, mental and spiritual treatment. The treatment for Lah disease in the infant and toddler revealed that 95% of them would not have a retreatment and 5% would have a retreatment. Applying herbs and incantation was for the physical, mental and spiritual treatment, and this research was useful for public health and medical system to integrate the knowledge with their treatments, decrease the government expenses on the current medicine, conserve the knowledge of folk doctor and improve for the international acceptance.