Diarrhea

Diarrhea can occur as a symptom of ME/CFS. It forms part of a wider range of gastrointestinal disturbances in ME/CFS, and sometimes forms part of a diagnosis of IBS, a common comorbidity.

Prevalence

 * In 1995, Katrina Berne, PhD, reported a prevalence of 50-90% for IBS symptoms (including diarrhea, nausea, gas, and abdominal pain).
 * In a 2001 Belgian study, 40.8% of patients meeting the Fukuda criteria and 45.6% of patients meeting the Holmes criteria, in a cohort of 2073 CFS patients, reported diarrhea.

Symptom recognition
Gastrointestinal issues (diarrhoea, constipation, acid reflux) as a group are a potential symptom of Long COVID in the World Health Organization's definition.