Objective : Diarrhea is defined as an increased frequency of stools(more than three per day), increased liquidity(loose or watery) and decreased consistency or stools. This study was done to examine the efficacy of Gwakhyang-junggisan for two patients who had suffered from chronic diarrhea of unknown origin on examination. At the time of admission, patients complained of diarrhea 4 or 5 times per day accompanied with epigastric discomfort, quadri pain. As of the fourth day of Gwakhyang-junggisan administration, the frequency and liquidity of diarrhea decreased and accompanying symptoms also improved. Method : Gwakhyang-junggisan was used for these patients suffering from chronic diarrhea of origin unknown to western medicine. patients were diagnosed as daejang-sul as bihu disease. Result : Results were taken as two cases of effective treatment of chronic diarrhea with Gwakhyang-junggisan. Conclusion : Result of this study suggest that Gwakhyang-junggisan is all effective treatment for such symptoms of chronic diarrhea as epigastric discomfort, quadri pain.