Clinical Use of Chai Ling Tang for Treating Fever of Unknown Origin

Fever of unknown origin (FUO) can be caused by many factors and usually presents as a high fever without a clear diagnosis. Although some treatments may relieve symptoms, they do not stabilise the condition and relapses are commonly reported. In this case, a 20-year-old male complained of recurring high fever (around 39-40 degrees Celsius) without reason for over two years. He had been hospitalised many times without a clear diagnosis. Applying fang zheng 方证 differentiation, the patient was prescribed Chai Ling Tang (Bupleurum and Poria Decoction) combined with Wai Tai Fu Ling Yin (Poria Decoction) as well as Ban Xia Hou Po Tang (Pinellia and Magnolia Bark Decoction). After three months of medication, the patient’s temperature stabilised, his body weight slowly increased and his other symptoms also improved.