Myalgic Encephalomyelitis (M.E.) is a debilitating neurological disease which has been recognised by the World Health Organisation (WHO) since 1969 as a distinct organic neurological disorder with the code G.93.3.
It can occur in both epidemic and sporadic forms, over 60 outbreaks of M.E. have been recorded worldwide since 1934.
M.E. is similar in a number of significant ways to illnesses such as multiple sclerosis, Lupus and Poliomyelitis (polio). Earlier names for M.E. were ‘atypical multiple sclerosis’ and ‘atypical polio.’
What defines M.E. is a specific type of acquired damage to the brain (the central nervous system) caused by a virus; an enterovirus.
Myalgic Encephalomyelitis is an acutely acquired neurological disease initiated by a virus infection with multi system involvement which is characterised by post encephalitic damage to the brain stem; a nerve centre through which many spinal nerve tracts connect with higher centres in the brain in order to control all vital bodily functions – this is always damaged in M.E. (Hence the name 'Myalgic Encephalomyelitis').
The term M.E. was coined in 1956 and means: My = muscle, Algic = pain, Encephalo = brain, Mye = spinal cord, Itis = inflammation. This neurological damage has been confirmed in autopsies of M.E. patients.
Myalgic Encephalomyelitis is primarily neurological, but also involves cognitive, cardiac, cardiovascular, immunological, endocrinological, metabolic, respiratory, hormonal, gastrointestinal and musculo-skeletal dysfunctions and damage. M.E. affects all vital bodily systems and causes an inability to maintain bodily homeostasis.
More than 64 individual symptoms of M.E. have been scientifically documented.
Encephalomyelitis can be more disabling than MS or polio, and many other serious diseases. M.E. is one of the most disabling diseases there is. More than 30% of M.E. patients are housebound, wheelchair-reliant and/or bedbound and are severely limited with even basic movement and communication. In some cases Myalgic Encephalomyelitis is fatal.
Why are Myalgic Encephalomyelitis patients so severely and uniquely disabled? For a person to stay alive, the heart must pump a certain base-level amount of blood. Every time a person is active, this increases the amount of blood the heart needs to pump. Every movement made or second spent upright, every word spoken, every thought thought, every word read or noise heard requires that more blood must be pumped by the heart.
However, the hearts of M.E. patients only pump barely pump enough blood for them to stay alive. Their circulating blood volume is reduced by up to 50%. Thus M.E. patients are severely limited in physical, cognitive and orthostatic (being upright) exertion and sensory input.
This problem of reduced circulating blood volume, leading to cardiac insufficiency, is why every brief period spent walking or sitting, every conversation and every exposure to light or noise can affect M.E. patients so profoundly. Seemingly minor 'activities' can cause significantly increased symptom severity and/or disability (often with a 48-72 hour delay in onset), prolonged relapse lasting months, years or longer, permanent bodily damage (eg. heart damage or organ failure), disease progression or death.
If activity levels exceed cardiac output by even 1%, death occurs. Thus the activity levels of M.E. patients must remain strictly within the limits of their reduced cardiac output just in order for them to stay alive.
M.E. patients who are able to rest appropriately and avoid severe or prolonged overexertion have repeatedly been shown to have the most positive long-term prognosis.
Myalgic Encephalomyelitis is a testable and scientifically measurable disease with several unique features that is not difficult to diagnose (within just a few weeks of onset) using a series of objective tests
. If all tests are normal, then a person does not have M.E.This is not simply theory, but is based upon an enormous body of mutually supportive research and clinical information. Confirmation of this hypothesis is supported by electrical tests of muscle and of brain function and by biochemical and hormonal assays.
M.E. is an infectious neurological disease which affects all races and socio-economic groups and has been diagnosed all over the world with a similar strike rate to multiple sclerosis. Children as young as five can get M.E., as well as adults of all ages.
Governments around the world are currently spending $0 a year on M.E. research. (See below for references for this text.)
For more information see:
What is Myalgic Encephalomyelitis? A historical, political and medical overview of M.E.
Myalgic Encephalomyelitis: The Medical Facts A purely medical overview of the illness including detailed research findings.
Testing for Myalgic Encephalomyelitis An overview of some of the series of tests which can be done to help confirm a suspected M.E. diagnosis.
Because hummingbirds are tough little things with a lot more strength, bravery and determination than most people ever give them credit for - a lot like many of the people who have Myalgic Encephalomyelitis (M.E.)

All of the information concerning Myalgic Encephalomyelitis on this website is fully referenced and has been compiled using the highest quality resources available, produced by the world's leading M.E. experts.
More experienced and more knowledgeable M.E. experts than these – Dr Byron Hyde and Dr. Elizabeth Dowsett in particular – do not exist.
Between Dr Byron Hyde and Dr. Elizabeth Dowsett, and their mentors the late Dr John Richardson and Dr Melvin Ramsay (respectively), these four doctors have been involved with M.E. research and M.E. patients for well over 100 years collectively, from the 1950s to the present day. Between them they have examined more than 15 000 individual (sporadic and epidemic) M.E. patients, as well as each authoring numerous studies and articles on M.E., and books (or chapters in books) on M.E. Again, more experienced, more knowledgeable and more credible M.E. experts than these simply do not exist.
This paper is merely intended to provide a brief summary of some of the most important facts of M.E. It has been created – by a well-read layperson purely for the benefit of those people without the time, inclination or ability to read each of these far more detailed and lengthy references created by the world’s leading M.E. experts. The original documents used to create this paper are essential additional reading however for any physician (or anyone else) with a real interest in Myalgic Encephalomyelitis: For more information see the References page.
To read a fully referenced version of all of the information about M.E. given on this page, see the paper: Myalgic Encephalomyelitis is not fatigue, or 'CFS' and What is Myalgic Encephalomyelitis? Extra extended version.
Hummingbirds - an essay expanding on the idea of hummingbirds as a metaphor for severe Myalgic Encephalomyelitis. See also: The Hummingbird Gallery
M.E. vs MS: Similarities and differences M.E. and MS are very similar diseases medically in many ways. However, for reasons that have nothing to do with science, the two diseases are treated very differently politically and socially. The contrast could not be more stark. M.E. patients are treated terribly (and often abused terribly, even unto death in some cases), yet there is no public outcry as there would be if MS patients were treated in this same way. Thus people with M.E. find themselves in the terrible position of actually ENVYING people who have MS. new
Who benefits from 'CFS' and 'ME/CFS'? For whose benefit was ‘Chronic Fatigue Syndrome’ created, and for whose benefit is it so heavily promoted despite its utter lack of scientific credibility? Who benefits from Myalgic Encephalomyelitis and ‘CFS’ being mixed together through unscientific concepts such as ‘CFS/ME’ and ‘ME/CFS’ and Myalgic ‘Encephalopathy’? Who benefits from the facts of M.E. remaining ignored, obscured and hidden in plain sight? This paper looks at all of these very important questions. new
Smoke and mirrors This paper looks at the lack of evidence (and financial and political motivations) behind the 'behavioural' model of M.E. and outlines a strategy for the resolution of the confusion caused by the 'CFS' disease category.
The misdiagnosis of CFS None of the definitions of CFS defines M.E., so what do they define? What does a diagnosis of 'CFS' actually mean? See also: Where to after a 'CFS' (mis)diagnosis?
Why the disease category of ‘CFS’ must be abandoned M.E. and 'CFS' are not the same. This paper discusses why renaming, refining or sub-grouping 'CFS' cannot work and why 'CFS' must be abandoned.
What it feels like to have Myalgic Encephalomyelitis: A personal M.E. symptom list and description of M.E. This paper combines the available research on M.E. with a personal description of the illness to try to explain what it really feels like to have M.E. This is not just another 'list' of symptoms - more than 50 individual symptoms (and other characteristics) of M.E. have been described in detail.
The Ultra-comprehensive Myalgic Encephalomyelitis Symptom List. Most symptom lists are based on the bogus 'fatigue' model and so leave out all the neurological, cardiac, cardiovascular, immune system and other symptoms which truly define the illness. This is a comprehensive symptom list.
The effects of CBT and GET on patients with Myalgic Encephalomyelitis This paper looks at the physical effects of CBT (psychotherapy) and GET (exercise) on patients with M.E.
The myths about Myalgic Encephalomyelitis lists some of the most common myths about the illness.
See the Articles sorted by Author page for a full list of original articles available on this site.
The Ultra-comprehensive Myalgic Encephalomyelitis Symptom List. A comprehensive symptom list is an important tool for anyone with M.E.
Treating Myalgic Encephalomyelitis - The Basics Or: 'Help, I have M.E.- what on earth do I do now? Help!!!' is a guide to some of the basics you need to know to live with, cope with and to treat M.E.
Treating Myalgic Encephalomyelitis - Avoiding Overexertion Everything you need to know about the single most important thing you can do to give yourself the best chance at your best possible prognosis.
3 Part Myalgic Encephalomyelitis Ability and Severity Scale A valuable tool for monitoring the course of your illness over time.
A Million Stories Untold This paper is designed to help explain to a sufferers family members and friends that M.E. has nothing to do with being tired and that all the rumours they may have heard about it (and about 'CFS') aren't true. It explains all the facts using hard evidence from the world's leading M.E. experts and is fully referenced. A must-read for friends and family members.
Problems with 'our' M.E. (or 'CFS' 'CFIDS' or 'ME/CFS' etc.) advocacy groups
Problems with the use of 'ME/CFS' by M.E. advocates
Are we just 'marking time?' This paper looks at the problems with the flawed (but popular with some advocates) 'until we have a unique test for M.E. and more research, we can't expect anything to change' approach to M.E. advocacy. It asks the question; why are we waiting to act when tests for M.E. exist RIGHT NOW, and the need for activism and action is so very urgent? *new*
Other site features include: Activism Gear, Practical tips for living with Myalgic Encephalomyelitis, Support Groups and Contribute to this site. For a full list of the resources on this site available for patients (or doctors or carers and so on), see the Information Guides page.
This website has become so large that its features can no longer all be taken in at a glance. In order for site visitors to find the information they need more quickly, this page features Information Guides relevant to each of the different types of visitors to the site. Guides available so far include the following: (click on the most appropriate description)
The book: The Clinical and Scientific Basis of Myalgic Encephalomyelitis edited by Dr Byron Hyde is vital reading for anyone with an interest in M.E.
This book provides, in one superb 75-chapter source, an up-to-date, comprehensive account of current knowledge concerning the history, epidemiology, children with M.E., investigation, virology, immunology, muscle pathology, host response, food intolerance, brain mapping, neurophysiology, neuropsychology, sleep dysfunction and much more. This is an essential reference book for medical, government and public library reference rooms. This text is a unique vehicle for researchers, physicians and other health education and government officials, and is also easily understandable by the general public. All funds from the sale of this book go towards M.E. research and advocacy. See the Review of this book for more information and for purchasing details. (There is currently a special offer on this book and it is available for just $49!)
Dr Byron Hyde is the world's preeminent ME authority.
See also: A New and Simple Definition of Myalgic Encephalomyelitis and a New Simple Definition of Chronic Fatigue Syndrome & A Brief History of Myalgic Encephalomyelitis & An Irreverent History of Chronic Fatigue Syndrome (an extract) and The Complexities of Diagnosis by Dr Byron Hyde (and more) available online. *HIGHLY RECOMMENDED*
Dr Hyde's latest paper is also a MUST-READ: The Nightingale Definition of M.E.
More essential reading on M.E.:
To read more articles by any of these authors see: Articles sorted by Author
It is important to be aware that Myalgic Encephalomyelitis and 'CFS' are not synonymous terms and should not be used interchangeably, and that 'fatigue' is not a defining nor even essential feature of M.E. M.E. is defined by a variety of serious (testable) neurological, cardiac, cardiovascular, metabolic and other abnormalities - not by mere 'fatigue.'
Myalgic Encephalomyelitis is a distinct, scientifically verifiable and measurable, acute onset, organic neurological disease. ‘CFS’ in contrast, is not a distinct disease. ‘CFS’ doesn’t exist. Every diagnosis of CFS – based on any of the CFS definitions – can only ever be a misdiagnosis.
CFS was created in the 1980s in the US in response to an outbreak of what was unmistakably M.E., but this new name and definition did not describe the known signs, symptoms, history and pathology of M.E. It described a disease process that did not, and could not exist. The fact that a person qualifies for a diagnosis of 'CFS' (a) does not mean that the patient has Myalgic Encephalomyelitis (M.E.), and (b) does not mean that the patient has any other distinct and specific illness named ‘CFS.’
The bogus disease category of ‘CFS’ has undoubtedly been used to impose a false psychiatric paradigm of M.E. by allying it with psychiatric fatigue states and various unrelated fatigue syndromes for the benefit of insurance companies and various other organisations and corporations which have a vested financial interest in how these patients are treated, including the government.
The terminology is often used interchangeably, incorrectly and confusingly. However, the DEFINITIONS of M.E. and CFS are very different and distinct, and it is the definitions of each of these terms which is of primary importance. The distinction must be made between terminology and definitions.
Chronic Fatigue Syndrome is an artificial construct created in the US in 1988 for the benefit of various political and financial vested interest groups. It is a mere diagnosis of exclusion (or wastebasket diagnosis) based on the presence of gradual or acute onset fatigue lasting 6 months. If tests show serious abnormalities, a person no longer qualifies for the diagnosis, as ‘CFS’ is ‘medically unexplained.’ A diagnosis of ‘CFS’ does not mean that a person has any distinct disease (including M.E.). The patient population diagnosed with ‘CFS’ is made up of people with a vast array of unrelated illnesses, or with no detectable illness. According to the latest CDC estimates, 2.54% of the population qualify for a ‘CFS’ (mis)diagnosis. Every diagnosis of ‘CFS’ can only ever be a misdiagnosis.
Myalgic Encephalomyelitis is a systemic neurological disease initiated by a viral infection. M.E. is characterised by (scientifically measurable) damage to the brain, and particularly to the brain stem which results in dysfunctions and damage to almost all vital bodily systems and a loss of normal internal homeostasis. Substantial evidence indicates that M.E. is caused by an enterovirus. The onset of M.E. is always acute and M.E. can be diagnosed within just a few weeks. M.E. is an easily recognisable distinct organic neurological disease which can be verified by objective testing. If all tests are normal, then a diagnosis of M.E. cannot be correct.
M.E. can occur in both epidemic and sporadic forms and can be extremely disabling, or sometimes fatal. M.E. is a chronic/lifelong disease that has existed for centuries. It shares similarities with MS, Lupus and Polio. There are more than 60 different neurological, cognitive, cardiac, metabolic, immunological, and other M.E. symptoms. Fatigue is not a defining nor even essential symptom of M.E. People with M.E. would give anything to be only severely ‘fatigued’ instead of having M.E. Far fewer than 0.5% of the population has the distinct neurological disease known since 1956 as Myalgic Encephalomyelitis.
For more information on why the bogus disease category of 'CFS' must be abandoned for the benefit of all the patient groups involved, (along with the use of other vague and misleading umbrella terms such as ‘ME/CFS’ ‘CFS/ME’ 'CFIDS' and 'Myalgic Encephalopathy' and others, including 'ICD-CFS') see: The misdiagnosis of CFS, Why the disease category of ‘CFS’ must be abandoned, The Terminology Explained and What is M.E.? Extra extended version. See also: Who benefits from 'CFS' and 'ME/CFS'?