If you are new to helminthic therapy, it's best to start by reading the Introduction to helminthic therapy. While the introduction is not set out in the FAQ format, it is the most comprehensive and up-to-date guide to everything you need to know in order to understand and get started with this therapy. Its contents form a foundation to the rest of the material on this site and include details about the special types of helminth which are used in therapy and the companies that supply them. Reading the introduction carefully, and in full, will help to prevent you wasting time and money and possibly not getting the best from the therapy, if you decide to try it.
How do I get started with helminthic therapy?
This section is for those who want to cut to the chase.
1. Read the Introduction to helminthic therapy.
2. Check the Helminthic therapy personal stories page for the conditions you would like to treat. Reading these stories will help you decide which helminth species might best meet your needs.
3. Read more about these species on the Selecting a therapeutic helminth page, and note that the first inoculation should be with a single species.
4. See one, or more, of the following pages, as appropriate.
5. Once you have decided which species you would like to start with, check the Helminth providers page to find companies that supply this organism and ship to your location.
6. Check out the customer feedback about all the providers on the Helminth provider reviews page.
7. If you are hypersensitive or have one of several particular conditions, make sure to start with an appropriately small dose, especially if you are going to be using NA, in which case, see Hookworm dosing in a nutshell.
FAQs for newbies
What is helminthic therapy?
Helminthic therapy is the reintroduction to the digestive tract of a controlled number of specially domesticated, mutualistic helminths (intestinal worms) in the form of microscopic eggs or larvae to reconstitute a depleted biome to treat and prevent chronic inflammation, autoimmune disease and other immunological disorders including allergy.
To learn more, see this introduction to the topic.
Is helminthic therapy safe?
Yes, it is very safe, as can be seen from the details on the following page.
Is helminthic therapy legal?
In the United States, the FDA have issued an Import Alert which states that helminths used as immunomodulators are considered to be biological products as defined in Section 351 of the Public Health Service Act. This alert is the Agency's current guidance to FDA field personnel and authorises US Customs staff to confiscate packages they identify as containing helminth products.
However, there is no specific law prohibiting self-treatment with helminths, or prohibiting the sale, purchase, possession or growing of helminths for self-treatment, anywhere in the world, and, in practice, very few packages containing helminth eggs or larvae are intercepted in transit, even in the US. Most people who are self-treating with helminths are therefore able to receive deliveries from the helminth providers without issue.
Australian, New Zealand and German Customs departments have been known to impound some packages from the helminth providers, although there are ways to avoid this hurdle, so anyone in these countries should talk to their provider about this.
The only country where a helminth has been approved by a national regulator is Thailand. The certificate issued by the Thai FDA approving TSO as a natural medicine translates into English as follows.
Isn’t helminthic therapy gross?
Anyone who knows that “helminths” are intestinal worms, but does not yet fully understand helminthic therapy, might think that this involves swallowing worms similar to those found in garden soil, or perhaps something like the images they’ve seen online of scary parasitic mini-monsters.
The truth is that the specially selected organisms used in helminthic therapy are microscopic when taken - effectively just another form of probiotic - and they are never seen by the self-treater at any time during the therapy. So it isn’t in the least bit gross if viewed on a rational level. But even someone with a family member who is using, and enjoying the benefits of this therapy, may not be able to bring themselves to try it.
Until the twentieth century, virtually the entire population of the planet was hosting one helminth or another, and, even today, there are more than 1,700 million global inhabitants who host at least one species of soil-transmitted helminth.
And worms are by no means the only life form being carried around by humans. Even in hygiene-conscious industrialised countries in the twenty first century, most of the population are unwittingly hosting demodex mites in their eyelashes. Related to spiders, and shaped like a slug with eight stumpy legs, these mites grow up to 0.4 millimetres long, live in human hair follicles and associated sebaceous glands and come out at night for a walkabout around their host's face, where they have sex before slithering back into their foliclular tunnels. 
In spite of its rather unattractive appearance, no one is making a fuss about hosting the Demodex mite, because they don’t know it’s there! And it’s arguably irrational to be repulsed by any other invisible non-pathogenic species, including a helminth, especially when it is mutualistic rather than parasitic, and has the potential to transform its host’s health and possibly even save their life, as is the case with the therapeutic helminths featured on this site. As one helminth self-treater has said:
Education about helminthic therapy may be the best antidote to any feelings of fear and disgust that it causes, so gradually learning about the therapy by reading this wiki may be helpful. And reading the following piece of research about the "yuk" factor may also help someone with worm phobia to understand their own response.
However, if worm phobia is still an issue, the following page offers a very simple, practical solution for this.
Can the worms hosted by self-treaters infect other people?
The worms used in helminthic therapy have been carefully selected to be safe, both for the person hosting them and for everyone else. These particular helminth species cannot escape their host and directly infect another individual, because, once they leave their host, they die.
These worms all reproduce by means of eggs which can only develop into a new generation of worms after they have been passed by their host and undergone incubation elsewhere.
HDC reproduction requires a multi-stage process involving both rats and beetles, and the eggs produced by the whipworms, TSO and TTO, require months of incubation before they can transform into infectious organisms. Even the eggs produced by the hookworm, NA, must incubate for at least 4 days in specific conditions before they can become infectious larvae capable of infesting a new host. For more detail, see the following page.
Why is helminthic therapy necessary?
Helminthic therapy has only become necessary because humans have adopted many practices (e.g., wearing shoes and using toilets) that interrupt the life cycles of helminths which our forebears had previously hosted for millions of years.
Helminths are now considered to be heirloom species that have coexisted and co-evolved with humans to the extent that we are now incomplete without them and depend on their presence for the optimal functioning of our immune systems. These mutualistic organisms train the developing immune system in infancy and continue to regulate immune function throughout life for as long as they remain with us. Helminthic therapy is therefore not like a drug treatment, but more a form of replacement therapy - putting back something we have lost but which we actually need.
Although some people with particular genetic profiles don’t develop autoimmune diseases or allergies as a result of being helminth deficient, there is evidence that even they can be susceptible to developing degenerative diseases because they lack the very efficient inflammation control that helminths provide.
How does helminthic therapy work?
The organisms used in helminthic therapy work as a result of the chemicals that they secrete to protect themselves from being ejected by their host and to keep their host alive for as long as possible.
Over millions of years of coevolution with humans and our primate ancestors, helminths have learned to evade most of what the human immune system can throw at them, and they do this by controlling inflammation. For more detail about how they achieve this effect, see the following page.
What are the benefits of hosting helminths?
Helminthic therapy modulates (normalises) the function of the immune system. This action controls inflammation and reduces autoimmunity and allergies. To see how these effects are achieved, go to the following page.
Since inflammation is involved in many diseases, its control has many benefits for helminth hosts. Diseases that have been successfully treated by helminthic therapy are listed on the following page.
In addition to treating existing disease, helminthic therapy can also prevent disease, as can be seen from the details on this page:
What conditions have been helped by helminthic therapy?
Conditions with the largest number of reported successes are Crohn’s disease, allergy, food intolerance and ulcerative colitis.
Other conditions with a high number of reports of success include multiple sclerosis (MS), eczema, irritable bowel syndrome (IBS), asthma, multiple chemical sensitivity (MCS), food allergy, anxiety, depression, autism, migraine and Sjogren’s syndrome.
In all, more than 150 conditions have been reported to have been successfully remediated by helminthic therapy. These are all listed on the following page along with thumbnail comments by the patients or their parents, and, in many cases, with links to their full reports.
How effective is helminthic therapy?
Most of the clinical trials set up to investigate the effectiveness of helminthic therapy have produced unreliable results due to poor trial design. (See Problems with clinical trials.)
In the first of these three studies, more than 250 personal experiences of self-treatment with helminths were examined to determine the extent to which this therapy had effectively treated the subjects’ disease(s), and/or produced side effects, and the study authors concluded:
The effectiveness of each of the four helminths currently used in therapy was summarised as follows.
Effectiveness of TSO
Effectiveness of NA
Effectiveness of TTO
Effectiveness of HDC
For a guide to the relative effectiveness of each of the available four helminth species in treating some of the more common medical conditions, see the details in the following table.
Further evidence for the effectiveness of helminthic therapy generally is presented throughout this wiki, for example on the following page.
How long does helminthic therapy take to effect a cure?
Helminthic therapy does not "cure" anything. The replacement of worms in a previously worm-free intestine restores an ancient symbiotic bond developed over millennia between worms and host which optimises immune function. The resulting improvement in immune balance mitigates against chronic inflammation, autoimmune disease and other immunological disorders including allergy and some neuropsychiatric conditions.  This results in improved health that continues for as long as the worms are present. For examples of these improvements, see the following pages.
How long does it take to see benefits?
Helminthic therapy is typically very slow to deliver benefits when compared with drugs. For the majority who respond to treatment with hookworms, consistent improvements do not usually materialise until at least 3 months after their first inoculation, with most people only seeing improvement in their condition between 3 and 5 months. Some may only start to improve between 6 and 12 months and a few may even have to wait for as long as 18-24 months. Response to the non-human helminths, TSO and HDC, is usually more rapid.
Once improvements do begin, some people can experience a sudden and dramatic reduction in symptoms while others may respond more gradually over a period of time, possibly three years or more. Improvements during the first 2 years are not always continuous because there can be periods of exacerbation during which symptoms may worsen again, albeit temporarily.
Helminthic therapy is not a one-size-fits-all solution, nor a one dose fix. Dosing needs to be tailored to the unique needs of each individual, and continued indefinitely in the vast majority of cases.
How long do the benefits last?
There are people who have been able to enjoy many years of relief from their disease(s) after taking only one or two courses of TSO, and this period of remission has been extended in some self-treaters by taking periodic maintenance doses. (For more detail, see this page section.) But only one case has been reported of someone remaining disease-free for a number of years after completing only one course of therapy with NA  , and there have not yet been any reports of HDC users having remained disease-free after stopping the treatment. While there may be cases that have not yet been reported, they are likely to be limited in number.
In the majority of cases, users of helminthic therapy need to continue to host worms in order to maintain the benefits. And, when this is done, there is no limit on the length of time that benefits can be enjoyed.
Which worm species are used in helminthic therapy?
Four species of benign helminth have been domesticated for therapeutic use.
Which is the best helminth to use?
See the following page.
How many helminths do you need to take?
The number of helminths that need to be inoculated, and how often these doses need to be repeated, is different for each species. There are full details on the following pages.
Where do you get helminths from?
See the details here:
How are helminths administered?
Three species (TSO, TTO and HDC) are taken orally in a drink, while NA is introduced percutaneously (via the skin). More details on the following page.
Where, and how long, do helminths live?
NA and HDC live in the small intestine. The whipworms (TSO and TTO) live in the large intestine.
NA are reported to survive in humans for 3-10 years  but to be capable of living for up to 15 years,  and possibly even 18 years. However, the experience of hookworm self-treaters suggests that they typically only survive for approximately 1-3 years, and sometimes for only a few months, depending on the strength of the individual host’s immune response. For more, see: Hookworm survival.
TT can survive in humans for more than 2 years, and there have been two reports of them showing up during colonoscopies 7 and 8 years post-inoculation. However, they may die in under a year.
TSO and HDC only survive in humans for 2-3 weeks, and a few people may need to re-dose every week with HDC, suggesting an even shorter lifespan for this species in some hosts. HDC may mature to adulthood in immunosuppressed adults, and colonise a very small percentage of young children, but TSO does not colonise.
More details on the following pages.
What side effects are experienced by people with helminths?
Side effects are usually transient and confined to the first two or three months after the first inoculation. They are also dose-dependent, so can be minimised by conservative dosing.
For more detail about the side effects that are associated with each off the helminth species, see the following pages.
Can helminths increase inflammation?
Once the immune system detects the presence of helminths, it attempts to dislodge and dispatch them by creating inflammation in the gut to produce a "weep and sweep" effect. The extent of this response is dose-dependent, which is why helminthic therapy should always commence with small doses.
The increased inflammation also extends to other tissues throughout the body. This is revealed in the results of various blood tests and reflected in the increase in eosinophil numbers shown in the following graph.
This inflammatory response to the initial introduction of worms can give rise to a variety of transitory side effects, seen most notably with hookworms (see Hookworm side effects) but, provided that dosing is not excessive, these peak at around 50 days after inoculation and gradually reduce between 50 and 100 days.
The inflammatory response to a second dose is typically muted, and is likely to be absent altogether after subsequent doses as a result of worms already in the colony effectively modulating the immune response. For more about this, see The effects of helminths on the immune system.
Can helminthic therapy help with haemochromatosis?
All the therapeutic helminths tend to normalise nutrient levels, especially where these had previously been low due to poor absorption or excessive bleeding in disorders such as Crohn's disease or ulcerative colitis.
However, there are undoubtedly a few people whose susceptibility to mineral deficiencies, including iron, can increase somewhat as a result of hosting the human hookworm, Necator americanus (NA). In these cases, it is possible that NA might help in a small way with iron overload disorders such as haemochromatosis (hemochromatosis), but it would likely take a large number of NA to achieve a meaningful reduction in iron load. For example, at least 300 NA are required to produce a noticeable effect on iron status in an individual on a "normal" First World diet and, even where NA does reduce iron levels somewhat, this species takes insufficient blood to be able to halt the organ damage that is caused in haemochromatosis by excess iron.
It is more likely that the Old World Hookworm, Ancylostoma duodenale (AD), would have an impact on haemochromatosis because it is reported to draw nine times more blood than NA. In the 1940s, AD was used successfully to treat 25 patients with polycythemia, which causes an abnormally high number of red cells in the blood,  but between 300 and 600 AD were given to each of these patients, and this species is not currently available for therapeutic use.
There is a very small possibility that the human whipworm, Trichuris trichiura (TT) may cause anaemia in the long term, but the type of anaemia in this case is not due to low iron. It is speculated to be due to active suppression of the formation of blood cellular components in the bone marrow, rather than bleeding.
Can helminthic therapy help patients with cardiomegaly?
Whether or not hosting worms will help a particular individual with cardiomegaly will depend on the cause of this condition in their case.
"Cardiomegaly is not a disease, but rather a condition that can result from a host of other diseases such as obesity or coronary artery disease... The causes of cardiomegaly vary from patient to patient, depending on each case. Many times this condition results from high blood pressure (hypertension) or coronary artery disease." 
Helminthic therapy might help some people with cardiomegaly if the causes of this condition in their case involve the immune system and inflammation. By reducing systemic inflammation, worms are known to reduce the risk of cardiovascular problems generally. (See, Helminthic therapy for well people: Cardiovascular disease.)
What products and medications can harm therapeutic helminths?
See the following page.
FAQs about NA (the hookworm, Necator americanus)
How big should a hookworm colony be?
It’s pointless to even consider what the exact size of a hookworm colony might be because, firstly, there is no reliable test to determine the number of organisms being hosted, and, secondly, because worms are constantly dying due to unrelenting attrition by the immune system, the extent of which varies widely between different individuals.
All that can be determined about the extent of hookworm colonisation is the number of larvae that a host has introduced via inoculation, and the dates of, or the intervals between, these inoculations.
It is also true that the total number of worms being hosted is not important for the purposes of helminthic therapy. What matters is the length of time that the host has been exposed to worm secretions, the benefits of which develop gradually as the worms and the host’s immune system negotiate their long-term relationship.
So all that is required for successful therapy with hookworms is that the colony is kept refreshed by adding periodic top-up doses, and, for most people, top-up doses don’t need to be very large. It's the regular repetition of dosing that is most important. For more details, see the the following links.
I've inoculated with too many hookworms. What should I do?
See the following page section.
Are tattoos contraindicated if you have hookworms?
Since hookworms secrete a small amount of anticoagulant to assist their digestive process, NA self-treaters are sometimes concerned that getting a tattoo could cause excessive blood loss. This is not the case, however, due to the minuscule amount of anticoagulant involved, the fact that its effect is mostly localised at the feeding sites and the small number of worms that are hosted. For more about this, see the following page section.
Can NA affect bile production?
There are approximately 70 different species of hookworm, some of which may enter the bile ducts of animals, blocking them and consequently reducing, or halting, bile flow. There are also human helminths that are known to do this, including the roundworm, Ascaris lumbricoides. However, this is not something that NA does in humans. See the following page section.
Might a genetic bottleneck weaken the domesticated NA stock?
See the following page section.
FAQs about TT/TTO (the human whipworm, Trichuris trichiura)
Does the human whipworm, TT/TTO, cause "whipworm disease”?
The human whipworm, Trichuris trichiura (TT/TTO), can certainly cause "whipworm disease” if it is hosted in very large numbers, but when this species is used in helminthic therapy, only very small numbers of organisms, or “light” infections, are used. The following quote is from the website of the US Government's Centers for Disease Control and Prevention.
If an individual who is hosting TT for therapeutic purposes experiences any side effects at all, these will typically be mild and limited to the first few weeks of treatment. See, Possible TT side effects.
For more detail about the therapeutic use of TT/TTO, see the following page.
FAQs published by the helminth providers
The following "Frequently Asked Questions" pages on the websites of the commercial helminth providers are an additional source of answers to questions about the therapy.
Alternatives to FAQs
There are several alternative ways to get answers to questions by drilling into the contents of this site using one or more of the tools at the following link.