The Use of Directed Probiotics in ME/CFS: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Inclusion Criteria: eligible if all of the following apply: * Meets IOM ME/CFS case definition criteria, * Co-morbid IBS: meets RomeIV criteria for alternating or diarrhea-predominant IBS as reported during screening (technically diagnosed by a physician), * Able to provide consent to study, * Patients of childbearing potential must practice effective contraception during the study and be willing to continue contraception for at least six months after the intervention, * agrees to participate in online surveys and follow-up visits. Exclusion Criteria: ineligible if any of the following apply: * Probiotics in the past eight weeks, * Antibiotics in the past eight weeks, * Pregnancy or lactating women, * Medical conditions including short bowel syndrome, celiac disease, biliary disease, pancreatitis, inflammatory bowel disease (Crohn's disease, ulcerative colitis), severe cardiovascular, neurological condition, or liver failure, * Gastrointestinal surgery within six months of study entry, * History of psychiatric disorder, alcohol or illicit drug abuse.