Helminthic Therapy Safety

Because this is an experimental therapy no one can know how safe it is. Having said that the organisms we use have been studied for approximately one hundred and fifty years, and so far as we are aware there is no evidence in the scientific or medical literature of harm at low infection numbers of either hookworm or whipworm. We commissioned a microbiologist to review the available literature when we started up which you can download here

Hookworm and whipworm are inherently safe, as a study of any parasitology text will demonstrate, at therapeutic doses. They are so safe that the American Centers for Disease Control (CDC), a branch of the National Institute of Health (NIH), advises doctors not to treat light hookworm or whipworm infections (It is a dynamic link, so I cannot link directly to the page on the NIH website. To see it and to find it on the web please download our FAQ here.).

Light infections are all we sell.

Our therapy is not associated with any documented or known risk. We have only observed short-lived episodes of intestinal upset, fatigue, fever and joint pain that resolve without intervention. No one we have treated has experienced anything more than temporary discomfort, and only a minority experience even that.

The presence of large numbers of worms can be a problem, this is primarily seen in less developed countries, when malnutrition is an important factor.(1) Neither worm we supply can reproduce inside a human host, nor is it possible to infect anyone around you. Whatever number of hookworms or whipworms are given to you, population within you remains constant and can not increase. It is for these reasons that treatment with our helminths presents no known risks, either to you or those around you.

There is a large amount of scientific literature on parasitic co-infection, and some of these co-infections, for example; mosquito transmitted malaria, are still some of the most important problems faced by modern medicine. There is no recorded incidence of similar parasitic infection involving hookworm or whipworm. Despite significant research in this area of medicine there has never been a report that hookworm or whipworm can transmit viruses, bacteria or fungi.

Please contact us to obtain full-text scientific papers regarding any aspect of helminthic therapy, including one we commissioned from an independent microbiologist.

As safe as it is I have been able to think of a scenario when someone could be harmed by helminthic therapy.

As with any infection the subject will experience an immune response that will include inflammation at the site of application but also systemically.

As a result anyone with acute arteriosclerosis is at risk of a heart attack from the inflammatory response, and in theory if their arteriosclerosis was very severe, that is if they were on the point of a heart attack anyway the immune response to hookworm or whipworm infection could cause a heart attack and therefore death or worse.

Having said that in providing helminths to well over a thousand people since 2007 no one has experienced more than transient symptoms of hookworm or whipworm infection lasting at most a few weeks.

Our Questionnaire is largely devoted to identifying those who should not use helminths or who need to be treated in particular ways to avoid side effects. 

Thanks to all that experience it is very rare that our clients experience anything more than a rash at the site of application for hookworms and minor intestinal upset due to either hookworms or whipworms.


(1) Simon Brooker, Jeffrey Bethony and Peter J. Hotez. Human Hookworm Infection in the 21st Century. Adv Parasitol. 2004; 58: 197–288.

(2) J Croese, J O’Neil, J Masson, S Cooke, W Melrose, D Pritchard and R Speare. A proof of concept study establishing Necator americanus (hookworm) in Crohn’s patients and reservoir donors. doi:10.1136/gut. 2005.079129 2006;55;136-137 Gut

(3) Kevin Mortimer, Alan Brown, Johanna Feary,* Chris Jagger, Sarah Lewis, Marilyn Antoniak, David Pritchard, and John Britton. Dose-Ranging Study for Trials of Therapeutic Infection with Necator americanus in Humans. Am. J. Trop. Med. Hyg., 75(5), 2006, pp. 914–920

(4) John Croese, Marnie J. Wood, Wayne Melrose, and Richard Speare. Allergy Controls the Population Density of Necator americanus in the Small Intestine. GASTROENTEROLOGY 2006;131:402– 409

(5) Alex Loukas, and Paul Prociv. Immune Responses in Hookworm Infections. Clinical Microbiology Reviews, 0893-8512/01/$04.000 DOI: 10.1128/CMR.14.4.689–703.2001Oct. 2001, p. 689–703

(6) S. M. Geiger, I. R. Caldas, B. E. Mc Glone, A. C. Campi-Azevedo, L. M. De Oliveira, S. Brooker, D. Diemert, R. Correa-Oliveira & J. M. Bethony. Stage-specific immune responses in human Necator americanus infection

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