Introduction: Acute flank pain (AFP) as a common chief complain has a wide spectrum of differential diagnosis in conventional medicine. Also, Iranian traditional medicine presents similar wideness of diagnoses, etiologies and therapeutics. This study evaluates and explains differential diagnosis of AFP in traditional medicine and compares them with new studies' results.

Materials and methods: This is a qualitative study which was done in library with evaluation of traditional sources and new articles in medicine. Content analysis has done around "acute flank pain" in ancient scientists' view and then results, comparison with results of new studies around this basic.

Results: this study categories differential diagnosis of AFP in both traditional and conventional medicine which helps us to present theory based on abilities of these two instructions and their ability to share and affect each other.

Conclusion: Unique theory of "reeh" (wind) in traditional medicine besides of bacterial etiology in conventional medicine, leads to development of more effective diagnostic and therapeutic algorithms in the basic of acute flank pain.