Your Definitive Guide To Intestinal Parasites: What They Are, Symptoms + How To Heal

How To Get Rid Of Intestinal Parasites- A Functional Medicine Perspective On This Insidious Health Problem

Creepy-crawlies aren’t just for Halloween. They could be creeping around inside you! That thought of alien-like creatures inhabiting your body is enough to give anyone the shivers, but parasites are a reality, and they could be feeding off you to survive. Many people suffer unknowingly from parasitic infections, which can cause a whole slew of symptoms far beyond simple gut dysfunction problems like bloating and heartburn.

As a functional medicine practitioner, I often detect parasitic infections in my patients. Parasites can be an underlying contributing factor to many chronic health problems and a big reason why previous attempts at healing have been unsuccessful.

Article continues below

Make Your Life a Cleanse



Get FREE access to these + giveaways, recipes, & discount codes in personal emails from Dr. Will Cole.

Do you have intestinal parasites?

The shocking reality is that most everyone has some sort of parasite. Yes, even healthy people with no symptoms. Children and adults with weakened immune systems are most at risk for contracting parasites, but it can happen to anyone. The question is whether or not these parasites are fueling disease or fueling health (because weirdly, sometimes parasites are useful for health). It’s when we experience an overload or infection of parasites that these organisms cause a problem, and when parasites do cause symptoms, they can be life-altering. Some of the most common symptoms and signs of intestinal parasites include:

  • Digestive problems, including unexplained constipation, diarrhea, or persistent gas
  • Skin issues, including unexplained rashes, eczema, hives, and itching
  • Muscle and joint pain
  • Fatigue, even when you get enough sleep
  • Never feeling full, even after eating a big meal
  • Constant hunger, even when you are eating enough
  • Iron deficiency anemia (lab tests show an abnormally low iron level)
  • Grinding your teeth during sleep
  • Unexplained feelings of anxiety
  • Recurrent yeast infections
  • Itching of the anus or vagina

There are two kinds of common parasitic infections:


These parasitic worms live inside the GI tract and although they do not typically result in acute health issues, they can contribute to long-term, sometimes severe, chronic health problems because of the way they deplete the body’s resources. The most common helminths are tapeworms, roundworms, flatworms, hookworms, and whipworms. Pinworms, whipworms, and hookworms are all types of roundworms (1) that can cause digestive problems, mood swings, abdominal pain, brain fog, and weight loss. Hookworms, in particular, can work their way outside the gut lining to feed on your blood, leading to anemia.

Tapeworms are types of flatworms that live inside your intestine and can grow up to 35 feet long, laying close to one million eggs per day. They eat the food you eat and can cause feelings of constant hunger and are commonly contracted through eating undercooked contaminated meat. (2)

Protozoan parasites:

Single-cell protozoan parasites, like giardia, can multiply in your body and can contribute to acute health issues, such as extreme diarrhea. If left untreated, this could lead to severe dehydration, and even death.

How did I get a parasite?

You may think you have to travel to faraway destinations to contract a parasite, but that’s a myth. It is estimated that close to 37 percent of people worldwide (3) have some sort of helminth parasite, and there are many ways this happens.

One of the most common ways of contracting a parasite is through contaminated food, like undercooked meat or from drinking water. You can also get parasites through contact with contaminated feces (meaning: wash your hands after you use the bathroom - if everyone did, it could largely decrease the spread of the microscopic eggs of parasites).

But parasites don’t have to be a problem. Because they feed off of what you eat and thrive on junk food - sugar, in particular - upgrading your diet could help solve your parasite problem. Parasites are also more likely to multiply in people with microbiome imbalances or compromised immune systems. Being in poor health is basically throwing open the door for these invaders to establish themselves in your body, taking up residence and slowly feeding off your inner resources. This can cause nutrient deficiencies; a suppressed immune system, which can further perpetuate disease; and severe gut dysfunction. Perhaps you can see how this is a vicious cycle - poor health weakens the immune system, thus attracting parasites, and an overgrowth of parasites weakens your health even more.

Beneficial parasites

The very word “parasite” sounds dangerous and destructive, but believe it or not, in some cases, parasites can actually be beneficial, especially for people with autoimmunity. In the presence of parasites, Th1 and Th17 inflammatory cells get turned off, quelling chronic inflammation and actually increasing immune-balancing (regulatory T-) cells. There is so much evidence to support this that helminthic therapy is on the rise for many people struggling with autoimmune and other inflammatory conditions. In other words, people are purposefully infecting themselves with helminth parasites! While this may seem extreme, studies have shown that this therapy can greatly reduce the symptoms of autoimmune conditions, (4) such as multiple sclerosis (MS), asthma, inflammatory bowel conditions (Crohn’s and ulcerative colitis), and type 1 diabetes.

Taking this a step further, scientists have developed something called the hygiene hypothesis, (3) which theorizes that the significant reduction of exposure to parasites in industrialized nations is a major reason why the incidence of autoimmune conditions continues to rise - conditions that are virtually nonexistent in developing nations where parasites are more common.

According to this hypothesis, more sanitary conditions that reduce exposure to microorganisms increases the likelihood of the immune system becoming over-reactive, which increases the likelihood of developing autoimmune diseases (5) in response to exposure to toxins, a poor diet, and other environmental factors. The simple fact is that for thousands of years, humans have co-evolved with helminths, and since the goal of any living thing - parasites included - is to stay alive, these parasites have evolved to tolerate and even modulate the human body’s immune system to avoid being eliminated. If a parasite can sidestep immune system attacks, but not suppress the immune system to the point of compromising the health of the host (that’s you), then parasite and human can co-exist.

Helminths can also modulate the human microbiome - their presence can increase good bacteria in the gut. (6) Since around 75 percent of your immune system is located in your microbiome, helminths contribute to healthy functioning in multiple ways. It almost makes you want to go play in the dirt, making nice with these friendly parasites once more.

Helminthic therapy is not widely available in the United States but is an emerging therapy in the world of holistic and functional medicine. If you are interested in trying this therapy, it is important to work with a reputable doctor. Never buy helminths over the internet, as there are many possible side effects and this should only be done under the supervision of a knowledgeable practitioner.

Parasite lab tests

If you suspect your symptoms are due to a parasitic infection, there are a few ways to know for sure, so you and your doctor can start target treatment accordingly. These are the tests I use to detect parasitic infection:

1. Comprehensive stool test

This test looks for the ova, or eggs, of a parasite in your stool, to determine the presence of an infection.

2. Endoscopy and colonoscopy

If a stool test fails to find any parasites but your doctor still suspects an infection, he or she can examine your intestines with a camera, located at the end of a tube inserted through either your mouth (endoscopy) or rectum (colonoscopy), to look for signs of parasites.

3. Blood tests

Blood tests look for specific types of parasitic infections. A serology test looks for antibodies produced when the body is infected with a parasite, and a blood smear looks for parasites in the blood by examining the sample under a microscope.

How to cure your parasite infection

In conventional medicine, anti-parasitic drugs, such as praziquantel and mebendazole, are the first line of defense. The problem is that these drugs can cause many uncomfortable side effects (7) that can be almost as bad as the parasitic infection itself, including nausea, vomiting, headaches, weight loss, and insomnia. The damage parasites have caused before treatment will determine if you need additional pharmaceutical intervention, but there are many natural herbs that possess powerful anti-parasitic properties. These are great options if you want to take a completely natural approach or want to take something alongside anti-parasitic medications in accordance with your doctor’s recommendations.

Some of the ones I like to use with my patients include:

Something to be aware of if you are treating a parasitic infection in a way that removes the parasites quickly: the possibility of a Jarisch-Herxheimer reaction. When you attempt to kill off and rid yourself of parasites, they release toxins as they die off. Without proper liver support during this time, your body may respond to this elevated toxin load with uncomfortable detox symptoms, like headaches or the exacerbation of current symptoms. Basically, your symptoms can get worse before they get better. It is important to remember to start with a low dosage of either pharmaceutical or herbal anti-parasitics, and gradually work your way up to a full dose, to avoid this reaction as much as possible (but again, talk to your doctor to figure out what’s best for you).

When you look at the big-picture, we can’t really say that parasites are all bad or all good, but what we do know is that their microscopic size belies the immense power they can have over our health. By living a healthy lifestyle, we can keep these parasitic infections at bay…but we may not want to say goodbye to our old friends forever. We might just need them again someday.

As one of the first functional medicine telehealth clinics in the world, we provide webcam health consultations for people around the globe. 


Start Your Health Journey Today



  1. Roundworms Cleveland Clinic July 2013.
  2. Tapeworm Infection Mayo Clinic
  3. Versini, M., Jeandel, P., Bashi, T. et al. Unraveling the Hygiene Hypothesis of helminthes and autoimmunity: origins, pathophysiology, and clinical applications. BMC Med 13, 81 (2015).
  4. Smallwood TB, Giacomin PR, Loukas A, Mulvenna JP, Clark RJ, Miles JJ. Helminth Immunomodulation in Autoimmune Disease. Front Immunol. 2017;8:453. Published 2017 Apr 24. doi:10.3389/fimmu.2017.00453
  5. Okada H, Kuhn C, Feillet H, Bach JF. The 'hygiene hypothesis' for autoimmune and allergic diseases: an update. Clin Exp Immunol. 2010;160(1):1-9. doi:10.1111/j.1365-2249.2010.04139.x
  6. Lee SC, Tang MS, Lim YA, et al. Helminth colonization is associated with increased diversity of the gut microbiota. PLoS Negl Trop Dis. 2014;8(5):e2880. Published 2014 May 22. doi:10.1371/journal.pntd.0002880
  7. Antiparasitic Treatment CDC October 2019.
  8. Krishna S, Bustamante L, Haynes RK, Staines HM. Artemisinins: their growing importance in medicine. Trends Pharmacol Sci. 2008;29(10):520-527. doi:10.1016/
  9. Force M, Sparks WS, Ronzio RA. Inhibition of enteric parasites by emulsified oil of oregano in vivo. Phytother Res. 2000;14(3):213-214. doi:10.1002/(sici)1099-1573(200005)14:3<213::aid-ptr583>;2-u
  10. Fischer TC, Gosch C, Mirbeth B, Gselmann M, Thallmair V, Stich K. Potent and specific bactericidal effect of juglone (5-hydroxy-1,4-naphthoquinone) on the fire blight pathogen Erwinia amylovora. J Agric Food Chem. 2012;60(49):12074-12081. doi:10.1021/jf303584r
  11. Berberine. Altern Med Rev. 2000;5(2):175-177.
  12. Heggers JP, Cottingham J, Gusman J, et al. The effectiveness of processed grapefruit-seed extract as an antibacterial agent: II. Mechanism of action and in vitro toxicity [published correction appears in J Altern Complement Med 2002 Aug;8(4):521. Reagor Lana [corrected to Reagor Lee]]. J Altern Complement Med. 2002;8(3):333-340. doi:10.1089/10755530260128023
  13. Okeniyi JA, Ogunlesi TA, Oyelami OA, Adeyemi LA. Effectiveness of dried Carica papaya seeds against human intestinal parasitosis: a pilot study. J Med Food. 2007;10(1):194-196. doi:10.1089/jmf.2005.065
  14. Li T, Ito A, Chen X, et al. Usefulness of pumpkin seeds combined with areca nut extract in community-based treatment of human taeniasis in northwest Sichuan Province, China. Acta Trop. 2012;124(2):152-157. doi:10.1016/j.actatropica.2012.08.002
  15. Cortés A, García-Ferrús M, Sotillo J, Guillermo Esteban J, Toledo R, Muñoz-Antolí C. Effects of dietary intake of garlic on intestinal trematodes. Parasitol Res. 2017;116(8):2119-2129. doi:10.1007/s00436-017-5511-1

View More At Our Store

Purchase personally curated supplements
and Dr. Will Cole’s books!

Shop Dr. Will Cole

The information on this website has not been evaluated by the Food & Drug Administration or any other medical body. We do not aim to diagnose, treat, cure or prevent any illness or disease. Information is shared for educational purposes only. You must consult your doctor before acting on any content on this website, especially if you are pregnant, nursing, taking medication, or have a medical condition.

Our articles may include products that have been independently chosen and recommended by Dr. Will Cole and our editors. If you purchase something mentioned in this article, we may earn a small commission.



Evidence-based reviewed article

Dr. Will Cole, DNM, IFMCP, DC is a leading functional medicine expert who consults people around the globe, starting one of the first functional medicine telehealth centers in the world. Named one of the top 50 functional and integrative doctors in the nation, Dr. Will Cole provides a functional medicine approach for thyroid issues, autoimmune conditions, hormonal imbalances, digestive disorders, and brain problems. He is the host of the popular The Art Of Being Well podcast and the New York Times bestselling author of Intuitive Fasting, Ketotarian, The Inflammation Spectrum, and Gut Feelings: Healing the Shame-Fueled Relationship Between What You Eat and How You Feel.

Gut Feelings Dr. Will Cole 6

Gut Feelings

Healing The Shame-Fueled Relationship
Between What You Eat And How You Feel