ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

1–20 of 38 studies

E0 ConsensusPEM unclearModerate confidenceReview-NarrativeEditor reviewed

Causes of symptoms and symptom persistence in long COVID and myalgic encephalomyelitis/chronic fatigue syndrome.

Komaroff, Anthony L, Dantzer, Robert·Cell reports. Medicine·2025

This review examines why long COVID and ME/CFS cause such severe, lasting symptoms. Researchers found that both conditions share similar biological problems, including immune system misbehavior, problems with blood vessel function, and issues with how cells produce energy. The study suggests that symptoms may come from both these biological problems and from ancient survival responses in the brain that were meant to protect us during serious illness.

NeuroinflammationSevere MEGut Microbiome

E0 ConsensusPEM requiredModerate confidenceReview-NarrativeEditor reviewed

Gut Microbiome and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Insights into Disease Mechanisms.

Nikolova, Ralitsa, Donchev, Deyan, Vaseva, Katya et al.·International journal of molecular sciences·2025

This review examines the connection between gut bacteria and ME/CFS, a condition characterized by exhaustion that worsens after activity. The authors explain how an imbalance in gut bacteria may damage the intestinal barrier, allowing bacterial particles to enter the bloodstream and trigger inflammation throughout the body. They also discuss how changes in gut bacteria might affect the brain, contributing to the brain fog and cognitive problems many ME/CFS patients experience.

Gut MicrobiomeImmune SystemPost-Exertional Malaise

E0 ConsensusPEM unclearPreliminaryReview-NarrativeEditor reviewed

The potential therapeutic approaches targeting gut health in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): a narrative review.

Hsu, Chou-Yi, Ahmad, Irfan, Maya, Rana Warid et al.·Journal of translational medicine·2025

This review looked at how gut health might be connected to ME/CFS and found that people with ME/CFS often have different bacteria in their gut compared to healthy people. The researchers reviewed studies about various gut-focused treatments like probiotics, dietary changes, and other interventions that might help reduce ME/CFS symptoms by improving the gut-brain connection.

Gut Microbiome

E0 ConsensusPEM unclearModerate confidenceSystematic-ReviewEditor reviewed

Clinical evidence of the link between gut microbiome and myalgic encephalomyelitis/chronic fatigue syndrome: a retrospective review.

Wang, Jing-Hua, Choi, Yujin, Lee, Jin-Seok et al.·European journal of medical research·2024

Researchers reviewed 11 studies comparing gut bacteria in ME/CFS patients to healthy people. They found that people with ME/CFS have fewer types of bacteria and different bacterial communities in their guts compared to healthy controls. Additionally, ME/CFS patients produce lower levels of certain beneficial bacterial byproducts that are normally important for health.

Gut Microbiome

E0 ConsensusPEM unclearPreliminarySystematic-ReviewEditor reviewed

The impact of gut microbiome and diet on post-acute sequelae of SARS-CoV-2 infection.

Reyes, Zabrina, Stovall, Mary Catherine, Punyamurthula, Sanjana et al.·Journal of the neurological sciences·2024

This study looked at how gut bacteria and diet might affect people who develop Long COVID (symptoms that continue months after a COVID-19 infection). Researchers reviewed existing studies to see if changes in gut bacteria linked to worse COVID illness could be improved by eating foods rich in fiber and antioxidants, like those in the Mediterranean Diet. The idea is that a healthier gut might help prevent or reduce Long COVID symptoms.

Gut MicrobiomeImmune System

E0 ConsensusPEM unclearPreliminaryReview-NarrativeEditor reviewed

Persistent SARS-CoV-2 Infection, EBV, HHV-6 and Other Factors May Contribute to Inflammation and Autoimmunity in Long COVID.

Vojdani, Aristo, Vojdani, Elroy, Saidara, Evan et al.·Viruses·2023

This review examines how long COVID—a condition where symptoms persist months after a coronavirus infection—may develop through similar mechanisms to ME/CFS. The authors suggest that viral persistence, reactivation of old herpes viruses (like Epstein-Barr virus), immune system dysfunction, and gut microbiome changes may all contribute to ongoing inflammation and autoimmune problems. They propose testing for antibodies and other markers to better identify and treat long COVID.

Gut MicrobiomeImmune SystemLong COVID Overlap

E0 ConsensusPEM unclearPreliminaryReview-NarrativeEditor reviewed

Recognizing the Leaky Gut as a Trans-diagnostic Target for Neuroimmune Disorders Using Clinical Chemistry and Molecular Immunology Assays.

Simeonova, Denitsa, Ivanovska, Mariya, Murdjeva, Mariana et al.·Current topics in medicinal chemistry·2018

This review examines how a condition called 'leaky gut'—where the intestinal barrier becomes too permeable, allowing harmful bacteria to enter the bloodstream—may contribute to ME/CFS and other conditions affecting mood and energy. The authors summarize available blood and stool tests that can help doctors recognize leaky gut in practice. They identify specific markers (like immune responses to bacterial toxins and inflammatory proteins) that could signal intestinal barrier problems.

Gut MicrobiomeImmune System

E0 ConsensusPEM unclearPreliminarySystematic-ReviewEditor reviewed

A systematic review of enteric dysbiosis in chronic fatigue syndrome/myalgic encephalomyelitis.

Du Preez, S, Corbitt, M, Cabanas, H et al.·Systematic reviews·2018

Researchers reviewed seven studies looking at whether gut bacteria differences might cause ME/CFS symptoms. While all studies found some differences in gut bacteria between ME/CFS patients and healthy people, the findings were inconsistent and often not statistically significant. Currently, there isn't enough reliable evidence to say that abnormal gut bacteria are a major cause of ME/CFS.

Gut Microbiome

E0 ConsensusPEM not requiredPreliminarySystematic-ReviewEditor reviewed

Systematic review: faecal microbiota transplantation therapy for digestive and nondigestive disorders in adults and children.

Sha, S, Liang, J, Chen, M et al.·Alimentary pharmacology & therapeutics·2014

This review examined whether transferring stool bacteria from healthy donors to patients (called faecal microbiota transplantation or FMT) could help treat various diseases, including chronic fatigue syndrome. Researchers looked at 67 published studies involving 844 patients and found that FMT was very effective for certain gut infections and inflammatory bowel disease, with very few serious side effects reported.

Gut Microbiome

E1 ReplicatedPEM not requiredPreliminaryRCTEditor reviewed

Sijunzi decoction, a classical Chinese herbal formula, improves fatigue symptoms with changes in gut microbiota in chronic fatigue syndrome: A randomized, double-blind, placebo-controlled, multi-center clinical trial.

Dai, Liang, Liu, Zhidong, Zhou, Wenjuan et al.·Phytomedicine : international journal of phytotherapy and phytopharmacology·2024

This study tested whether Sijunzi decoction, a traditional Chinese herbal formula, could reduce fatigue in ME/CFS patients. Over 100 people with ME/CFS took either the herbal formula or a placebo for 2 months. The herbal treatment group showed slightly more improvement in fatigue symptoms and overall health than the placebo group, and the improvement may be linked to changes in gut bacteria.

Gut Microbiome

E1 ReplicatedPEM not requiredPreliminaryRCTEditor reviewed

Randomized, double-blinded, placebo-controlled pilot study: efficacy of faecal microbiota transplantation on chronic fatigue syndrome.

Salonen, Tapani, Jokinen, Elina, Satokari, Reetta et al.·Journal of translational medicine·2023

Researchers tested whether transplanting gut bacteria from healthy donors into ME/CFS patients could reduce fatigue and improve quality of life. Eleven patients received either bacteria from a healthy donor or their own bacteria (a placebo control) via colonoscopy, and their symptoms were tracked for six months. The treatment was safe, but it did not improve fatigue, pain, or overall quality of life compared to placebo.

Gut Microbiome

E1 ReplicatedPEM not requiredPreliminaryRCTEditor reviewed

[Ginger-separated moxibustion for chronic fatigue syndrome and its effect on intestinal flora].

Lin, Yu-Fang, Jin, Xiao-Qing, Zhu, Jian-Fang et al.·Zhongguo zhen jiu = Chinese acupuncture & moxibustion·2021

This study tested whether ginger-separated moxibustion (a traditional Chinese medicine technique involving heat applied to the skin over specific points) could help reduce fatigue in ME/CFS patients. Over 4 weeks, patients receiving moxibustion treatment along with normal diet and exercise showed significantly greater improvements in fatigue symptoms compared to those receiving diet and exercise alone. The treatment also appeared to change the types of bacteria in patients' guts in ways that might support better intestinal health.

Gut Microbiome

E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Assessment of the Gut Microbiome in Patients with Coexisting Irritable Bowel Syndrome and Chronic Fatigue Syndrome.

Chojnacki, Marcin, Błońska, Aleksandra, Kaczka, Aleksandra et al.·Nutrients·2025

This study looked at the gut bacteria and their byproducts in 80 women, comparing those with IBS alone to those with both IBS and chronic fatigue. Women with both conditions had different types of bacteria and different levels of certain chemicals in their urine, particularly those related to tryptophan (an amino acid). Higher levels of some of these chemicals were linked to worse fatigue symptoms.

Gut Microbiome

E2 ModeratePEM unclearModerate confidenceLongitudinalEditor reviewed

AI-driven multi-omics modeling of myalgic encephalomyelitis/chronic fatigue syndrome.

Xiong, Ruoyun, Aiken, Elizabeth, Caldwell, Ryan et al.·Nature medicine·2025

Researchers used artificial intelligence to analyze blood, gut bacteria, immune cells, and symptoms from 249 ME/CFS patients tracked over 4 years. The AI model discovered that ME/CFS involves abnormal patterns in gut bacteria products, blood fats, and immune cells that attack infections—particularly special T cells that become overactive. These findings suggest ME/CFS isn't caused by a single problem but by multiple connected systems going wrong together.

BiomarkersGut MicrobiomeEnergy MetabolismImmune System

E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

The gut microbial composition is different in chronic fatigue syndrome than in healthy controls.

Prylińska-Jaśkowiak, Monika, Tabisz, Hanna, Kujawski, Sławomir et al.·Scientific reports·2025

Researchers compared the bacteria living in the gut of people with ME/CFS to healthy people and found clear differences. People with ME/CFS had less diverse bacterial communities and different types of bacteria overall. A computer program could accurately tell the difference between ME/CFS and healthy people just by looking at their gut bacteria patterns, suggesting this difference might be important for the illness.

Gut Microbiome

E2 ModeratePEM unclearModerate confidenceCross-SectionalEditor reviewed

Systemic antibody responses against gut microbiota flagellins implicate shared and divergent immune reactivity in Crohn's disease and chronic fatigue syndrome.

Bourgonje, Arno R, Hörstke, Nicolai V, Fehringer, Michaela et al.·Microbiome·2024

This study looked at immune responses in ME/CFS and Crohn's disease patients by measuring antibodies against proteins from gut bacteria called flagellins. Researchers found that both patient groups had elevated antibodies against these bacterial proteins, but the pattern of where these antibodies attached differed between the two diseases. These antibody patterns could potentially help doctors diagnose ME/CFS and understand how the immune system may be responding abnormally to gut bacteria.

Gut MicrobiomeImmune System

E2 ModeratePEM unclearModerate confidenceObservationalEditor reviewed

Multi-'omics of gut microbiome-host interactions in short- and long-term myalgic encephalomyelitis/chronic fatigue syndrome patients.

Xiong, Ruoyun, Gunter, Courtney, Fleming, Elizabeth et al.·Cell host & microbe·2023

Researchers studied the gut bacteria and blood chemicals of people with ME/CFS to understand how the disease affects the body. They compared three groups: people with ME/CFS for less than 4 years, people who've had it for over 10 years, and healthy people without the disease. They found that early ME/CFS patients have significant changes in their gut bacteria, while long-term patients' bacteria had mostly normalized, but their blood chemistry and symptoms remained abnormal.

Gut Microbiome

E2 ModeratePEM not requiredPreliminaryCross-SectionalEditor reviewed

Associations between the gut microbiome and fatigue in cancer patients.

Hajjar, Joud, Mendoza, Tito, Zhang, Liangliang et al.·Scientific reports·2021

Researchers studied 88 cancer patients to see if the bacteria living in their gut were connected to cancer-related fatigue. They found that certain beneficial bacteria (Eubacterium hallii) were linked to lower fatigue levels, while other bacteria (Cosenzaea) were linked to higher fatigue. This suggests that the mix of gut bacteria might play a role in how tired cancer patients feel, opening the door to new treatments.

Gut Microbiome

E2 ModeratePEM unclearPreliminaryCross-SectionalEditor reviewed

Eukaryotes in the gut microbiota in myalgic encephalomyelitis/chronic fatigue syndrome.

Mandarano, Alexandra H, Giloteaux, Ludovic, Keller, Betsy A et al.·PeerJ·2018

This study looked at tiny organisms called eukaryotes (which include fungi and parasites) living in the gut of people with ME/CFS compared to healthy people. Researchers found that people with ME/CFS had slightly less diversity of these organisms and some differences in fungal types, though these differences were small. The findings suggest that gut imbalances in ME/CFS may involve more than just bacteria.

Gut Microbiome

E2 ModeratePEM not requiredPreliminaryObservationalEditor reviewed

Effect of supplement with lactic-acid producing bacteria on fatigue and physical activity in patients with chronic fatigue syndrome.

Sullivan, Asa, Nord, Carl E, Evengård, Birgitta·Nutrition journal·2009

This small study tested whether specific probiotic bacteria (live microorganisms that may benefit gut health) could reduce fatigue and improve physical activity in ME/CFS patients. Fifteen patients took probiotics for 4 weeks and were monitored for changes in fatigue, physical activity, and cognitive function. While some patients reported feeling better overall, the study did not find significant improvements in fatigue or activity levels, though cognitive function did improve.

Gut MicrobiomeImmune System

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Evidence browser

Causes of symptoms and symptom persistence in long COVID and myalgic encephalomyelitis/chronic fatigue syndrome.

Gut Microbiome and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Insights into Disease Mechanisms.

The potential therapeutic approaches targeting gut health in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): a narrative review.

Clinical evidence of the link between gut microbiome and myalgic encephalomyelitis/chronic fatigue syndrome: a retrospective review.

The impact of gut microbiome and diet on post-acute sequelae of SARS-CoV-2 infection.

Persistent SARS-CoV-2 Infection, EBV, HHV-6 and Other Factors May Contribute to Inflammation and Autoimmunity in Long COVID.

Recognizing the Leaky Gut as a Trans-diagnostic Target for Neuroimmune Disorders Using Clinical Chemistry and Molecular Immunology Assays.

A systematic review of enteric dysbiosis in chronic fatigue syndrome/myalgic encephalomyelitis.

Systematic review: faecal microbiota transplantation therapy for digestive and nondigestive disorders in adults and children.

Sijunzi decoction, a classical Chinese herbal formula, improves fatigue symptoms with changes in gut microbiota in chronic fatigue syndrome: A randomized, double-blind, placebo-controlled, multi-center clinical trial.

Randomized, double-blinded, placebo-controlled pilot study: efficacy of faecal microbiota transplantation on chronic fatigue syndrome.

[Ginger-separated moxibustion for chronic fatigue syndrome and its effect on intestinal flora].

Assessment of the Gut Microbiome in Patients with Coexisting Irritable Bowel Syndrome and Chronic Fatigue Syndrome.

AI-driven multi-omics modeling of myalgic encephalomyelitis/chronic fatigue syndrome.

The gut microbial composition is different in chronic fatigue syndrome than in healthy controls.

Systemic antibody responses against gut microbiota flagellins implicate shared and divergent immune reactivity in Crohn's disease and chronic fatigue syndrome.

Multi-'omics of gut microbiome-host interactions in short- and long-term myalgic encephalomyelitis/chronic fatigue syndrome patients.

Associations between the gut microbiome and fatigue in cancer patients.

Eukaryotes in the gut microbiota in myalgic encephalomyelitis/chronic fatigue syndrome.

Effect of supplement with lactic-acid producing bacteria on fatigue and physical activity in patients with chronic fatigue syndrome.

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