Chronic diarrhea is defined as the presence of ≥3 loose stools per day for more than 4 weeks.  Although stool weight has been used in scientific studies, it is not useful in clinical practice, as some patients may have increased stool weight (higher than normal fecal weight of 200 g/day) but normal stool consistency, therefore do not complain of diarrhea.  Diagnosis can be challenging as a large number of etiologies present in a similar way and range from benign to life threatening. A systematic method of evaluation, knowledge of the common causes, and an understanding of the local epidemiology are crucial for efficient and effective diagnosis and management of chronic diarrhea. 
Honorary Senior Lecturer
University of Manchester
SC declares he has no competing interests.
Clinical Research Fellow
University of Edinburgh
RK declares that he has received speaker fees from Ferring. He is also the author of a reference cited in this monograph.
Dr Simon Campbell and Dr Rahul Kalla would like to gratefully acknowledge Dr Abhishek Sharma, Dr Daniel Leffler, and Dr Ciaran Kelly, the previous contributors to this monograph. AS has received honoraria for educational presentations, chairing educational sessions, or advisory work from Abbvie, Vifor Pharma, Almirall, Falk, and Warner Chilcott UK. DL and CK are the authors of a number of references cited in this monograph.
Michigan State University
JK declares that he has no competing interests.
Professor of Gastroenterology
Imperial College London
JRFW has been a member of advisory boards and has received fees for arranging an educational programme from GE Healthcare, the manufacturer of 75SeHCAT. He is a member of the Health Advisory Network for Coeliac UK.
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