Abstract: Objective To retrospectively study the possible causes of rare green urine in order to provide reference for clinical diagnosis and treatment. Methods The clinical data about one patient who had been hospitalized because of fever, cough and discomfort, and green urine after taking Indigo Naturalis, was reported and analyzed with a literature review. Results The patient’s urine routine examination and other related laboratory examinations showed no abnormalities, but chromatographic analysis of the urine revealed Indigo Naturalis. After the patient was told to stop using traditional Chinese medicine and drink plenty of water, the urine returned to normal light yellow. Conclusion Such elements of traditional Chinese medicines as Indigo Naturalis might cause urine to turn green by staining, but this change is usually harmless and needs to be distinguished from other pathological conditions.

Key words: green urine, traditional Chinese medicine, Banlangen, Daqingye, Indigo Naturalis