Objective : The purpose of the present study was to report the improvement of functional abdominal pain in a patient treated with a herb medication based on a disease pattern identification diagnostic system under the provision of Shanghanlun (DPIDS). Methods : According to DPIDS, the patient was diagnosed with Taeyang-byung, no. 25 provision, and was administered with Gyejiyimahwangyil-tang herb medication for 60 days. The severity of the abdominal pain was assessed with the five-point Likert scale. Results : The abdominal pain in the patient disappeared following treatment with Gyejiyimahwangyil-tang, which is described in the 25th provision of Shanghanlun. Conclusions : The present case report suggests that '瘧', a word in the 25th provision of Shanghanlun may indicate severe abdominal pain at nighttime and not just malaria.