Enzyme Potentiated Desensitisation

Otherwise known as EPD!

I have been going to Dr Myhill's place in Mid Wales for a few years now to receive my jab of EPD.

For a description of what it does and how it works and what you can expect, I simply reproduce the relevant page from her website below.

My own personal experience is that this treatment contributed massively to my (ongoing) recovery. Along with having my mercury dental amagam fillings removed (which improved my cognitive function markedly) and the mito supplements (D Ribose etc which helped with physical symptoms), the EPD was vital in alleviating allergy symptoms.

As with many ME sufferers, I had heightened chemical and food sensitivities. Just driving past an Indian restaurant would make me feel awful - headaches, anxiety, weakness etc. Spice was one of my main allergen triggers. EPD has not solved all these problems but it has extended my diet and I no longer have allergy induced relapses.

EPD seems to work in other ways. I am due for an EPD shot today actually and because of all the GMC stuff that has gone on, I am overdue by 7 weeks (by the way, the time period between shots does extend and some people don't need to carry on at all but I still go about every 3 months). I really feel like I need this shot. Within about 2 days of having it, I know I will feel better and that this will last for about 3 months. I expect this time period of feeling better to continue to lengthen as time goes by.

Hope this helps.

Please ask any questions you may have and I will try to answer them or get the answer from someone who really knows!


Here is Dr Myhill's webpage:

Enzyme Potentiated Desensitisation (EPD) is a vaccine which can be used to desensitise patients to both foods, inhalants and chemicals. The vaccine has been developed and refined by Dr Len McEwen over the past thirty years. It is supplied to the doctor who mixes the appropriate dose in a sterile environment, immediately prior to dosing.

What the vaccine contains:
1-3 diol - a kind of alcohol which activates the enzyme. It is used in a tiny dose.

-glucuronidase - an enzyme. This appears to act as a lymphocyte hormone (lymphokine). It occurs naturally in human blood. The amount present in the vaccine is equivalent to that normally present in 1cc of normal plasma (white cells contain much more). In the vaccine it is thought to be responsible for stimulating the Langerhan cells to migrate to the local lymph glands and "reprogram" a new population of T suppressor lymphocytes. In the presence of antigen in the appropriate concentrations, this will result in a desensitisation. (Conversely in the presence of antigen at a "wrong" concentration you may get a hypersensitisation).

Antigen mixes:
The beauty of EPD is that one injection can be used to desensitise to a great many allergens. There are theoretical and practical reasons for preferring to desensitise with antigen mixes rather than so-called "single allergens". The following mixes are most frequently used:

"X" - mixed foods and additives, mixed moulds, mixed pollens, cat-dog, flock fly mix and bacterial mix.

"I" - inhalants alone. This is used to treat hay fever, cat, dog, horse allergy, pure mould and house dust allergy.

Separate mixes of "odds and ends", laboratory animals and sawdusts are also available.

"Fumes mix" - contains perfume oils, terpenes and other antigens which are not miscible with water unless they are extremely dilute.

Antigen Strengths
EPD works by manipulating the normal immune processes for creating and turning off allergies. Therefore success or failure depends largely on priming the patient in the best possible way. What makes EPD critical "θ" strength, the aim is to have approximately 10,000 molecules of each food antigen for desensitisation present at the injection site. Most patients receive Xθ for food allergy.

For inhalant desensitisation of the airways, the best dose (designated "C" strength) is equivalent to that received in a skin prick test. So most patients for seasonal hayfever or asthma would receive IC.
Patients with chemical sensitivity receive the fumes mix at θ strength.
Indications For Use
Any condition caused by allergy such as:

Asthma, eczema, rhinitis, chronic urticaria, angioneurotic oedema.
Hyperkinetic syndrome
Migraine and chronic headaches
Irritable bowel syndrome
Inflammatory bowel disease
Food induced psychological states - depression, anxiety.
Chronic fatigue syndrome
Multiple food allergy
In some instances, hyperventilation is caused by food allergy.
I do sometimes use EPD for the worst possible reason, that is I can't think of anything else to do when all else has been tried. However it is surprising how often this works! Hidden allergies to foods, inhalants and chemicals are common causes of recalcitrant symptoms. One of the joys of using EPD is that it desensitises to all allergens across the board, so it is not essential to know all ones allergies for it to work.

Does it work?
A pessimistic estimate would be that EPD will fail in about 20% of suitable patients with known allergies. The rest will experience varying degrees of improvement. Follow up studies after 5 years and double blind trials suggest that EPD has much greater long-term success than any other method of immunotherapy.

How soon will it work?
Because EPD relies on the production of a new generation of cells, the effect of each dose will not be fully developed for at least 3 weeks. Simple allergics, such as hay fever, usually respond to the first dose. But doses of EPD are cumulative and a few of the more complex allergic patients may not start to improve until 8 or more doses have been given. This is the case for many of my CFS patients.

How safe is EPD?
Approximately 350,000 treatments of EPD have been given world wide over the past 30 years. For patients with severe anaphylactic type reactions I first skin test with a tiny dose of antigen. If there is no reaction I then use the "cup" method whereby the epidermis of the skin is scraped off and the vaccine applied in a 1.5 ml hemispherical plastic container. This can be removed and antigen wiped off in the event of any reaction. About 100,000 treatments have been given by the "cup" method. There have been no life threatening reactions with EPD. It must always be remembered that when foreign antigen is injected the usual safety precautions should be taken. I always carry adrenaline, antihistamines, steroids etc but I have never had to use them, or even consider using them in any patient.

EPD by injection
However, nearly all treatments given by me are by injection - the enzyme and antigens are all given in one syringe, total volume of about 0.05ml as an intradermal injection. It feels like a bee sting and brings up a small white "lentil" sized lump on the forearm. After a few minutes this usually disappears, but some patients get slight redness and swelling at the injection site.

Allergen exposure and the time of treatment
Treatment for seasonal allergies should be given at least 4 weeks before the season begins. There is a theoretical risk that one might hypersensitise a patient if he/she is exposed to allergens at treatment time. However, I have now been using EPD for 12 years and have given over 4,000 treatments and have yet to be covinced that this is a real clinical problem. Therefore there are no special environmental precautions to take other than avoid known sensitivities.

Desensitisation for foods works best if the patient sticks to their "safe", ie non-reacting foods for the 24 hours before and 3 days after the EPD injection.

EPD and allergy to gut flora
It is not uncommon to see patients who have become sensitised to their own gut flora. In these cases it is necessary to reduce the antigen load starting 4 days prior to a dose of EPD.

The commonest problem is allergy and gut fermentation and drugs used to pretreat include Sporanox and nystatin powder.

Allergy to gut bacteria requires pretreatment with antibiotics.

For the next thrilling instalment, read... (see Dr Myhill's website for this)

EPD - the practical details of what to do for each dose

EPD trials
Published double blind trials have shown that EPD is effective in the treatment of seasonal hayfever and asthma (several trials ), ulcerative colitis, childhood migraine and hyperactivity. At the time of writing, EPD has also been successful in further double blind trials studying hay fever (4 trials) and childhood house dust mite asthma. The results of all these trials will be submitted for publication. Uncontrolled trials have also shown benefit in the treatment of eczema, irritable bowel syndrome, urticaria, rhinitis and asthma. Clinical experience from over 100 clinicians working world wide (and growing) is encouraging. More trials are urgently required. The American audit of EPD patients shows results that are so good that I can hardly believe them!


Senior Member
This is a great post and I love Dr Myhill dearly but just for balance I want to say I did react badly to EPD, at first I did get benefit not fatigue wise but certainly on the allergy side still had MCS but with hindsight compared to my current state not as severely as now and I give EPD at least partial credit for that. I currently have daily neutralization vaccines compared to them EPD is a breeze cheap, easy and an attractive proposition but it is a one size fits all and for some reason after a few years my allergies intensified after the injection - i persevered for a while as I read this can sometimes happen for a few weeks before improving, this never happened and it got so bad I had to test for neutralizing vaccines with some urgency. I may not be typical, I know I have all kinds of contray and weird reactions to lots of things plus I do have acute MCS and it did serve me well for a few years. I am just mentioning it because in the end I did get worse not better.



Desert of SW USA
Anyone have an update on experiences with Enzymes Potentiated Desensitization?