Intestinal Parasites: Signs You May Have One

Topic Overview

Intestinal parasites live in your gut and feed off you. You can pick them up from contaminated food, water, soil, animals, or person-to-person contact. Signs of intestinal parasites in humans include digestive changes, fatigue, anemia, skin irritation, teeth grinding, and sleep problems. These signs overlap with Candida and SIBO, so they are not a diagnosis. Take the Parasite Quiz, work with a qualified practitioner on stool testing, and follow the 3-Step Approach in order: Starve, Disrupt and Kill, Restore and Balance.

Table of Contents

1. Topic Overview
2. What Are Intestinal Parasites?
3. How Do You Get Intestinal Parasites?
4. Signs of Intestinal Parasites in Humans
5. How to Tell the Difference Between Parasites, Candida, and SIBO
6. Parasite Quiz
7. Intestinal Parasites, Hashimoto’s, and Graves’
8. How to Test for Intestinal Parasites
9. The 3-Step Approach to Solving Parasites

Having intestinal parasites can feel scary. You are not alone. The idea that they only exist in underdeveloped countries is a myth. I often saw them in my thyroid and autoimmune patients, and they can show up after travel, food poisoning, undercooked meat, or contaminated water right here at home.

Intestinal parasites are organisms that live and feed in your gut. Common intestinal parasites include protozoa such as Giardia and worms such as pinworms, hookworms, roundworms, whipworms, and tapeworms. (1,2,3) Gastrointestinal parasites symptoms range from diarrhea and bloating to fatigue, anemia, and sleep disruption. They do not, on their own, tell you which organism you have.

This is the first thing I want you to understand: “The gut is the gateway to health.” And the second: “If your gut is not healthy, neither are you.” Your gut is the foundation of your whole body’s health because 80% of your immune system resides there. Without a healthy gut, you can’t have a healthy immune system. If you have tried to heal your gut and still feel off, an intestinal parasite could be one of the infections standing in your way.

What Are Intestinal Parasites?

 A parasite is an organism that lives on or inside another organism. Intestinal parasites live in your intestines. Some are microscopic protozoa. Others are parasitic worms, also called helminths.

Common intestinal parasites include:

• Giardia, a tiny parasite that lives in the gut and comes out in stool (2)

• Pinworms, small white roundworms and the most common worm infection in the United States (4)

• Hookworms, which live in your small intestine and can enter through contaminated soil (3)

• Roundworms, whipworms, and tapeworms

Some consume nutrients from your meals and leave you hungry after you eat. Some attach to your intestinal wall and feed on blood, which can contribute to iron-deficiency anemia. (3) Pinworms lay eggs around the anus at night, which can cause itching and restless sleep. (4)

How Do You Get Intestinal Parasites?

Animals, food, water, soil, and other people can transmit parasites. (1)

You can get intestinal parasites from:

• Undercooked meat and raw fish such as sushi or sashimi

• Contaminated fruits and vegetables, especially produce you eat raw

• Swallowing untreated water from lakes, rivers, springs, pools, or splash pads (1,2)

• Walking barefoot on contaminated soil, which is how hookworm larvae can enter through your skin (3)

• Handling animals or animal environments contaminated with stool (1)

• Person-to-person spread when someone does not wash their hands after using the restroom, then touches a door handle, phone, food, or another person (2,4)

This is what causes intestinal parasites in real life: exposure, not a character flaw. Wash your hands with soap and water. Avoid swallowing lake or pool water. Cook meat thoroughly. If you drink untreated surface water, boil or filter it first. (1,2)

Signs of Intestinal Parasites in Humans

There are many types of parasites, so gastrointestinal parasites symptoms vary. Learning the pattern is useful. It is not a self-diagnosis.

Symptoms of gastrointestinal parasites in humans I watch for include:

1. Anemia. Hookworms attach to your intestinal wall and feed on blood. Heavy infections can lead to iron-deficiency anemia and fatigue. (3)

2. Appetite and satiety changes. Never feeling satisfied after meals, unexplained weight loss, nausea, or a drop in hunger.

3. Bruxism. Grinding your teeth in your sleep can travel with anxiety and sleep disruption.

4. Digestive woes. Unexplained constipation, diarrhea, gas, stomach cramps, or symptoms that resemble IBS. Giardia often brings diarrhea, gas, greasy stools, cramps, and nausea. (2)

5. Fatigue. Exhaustion, depression, or apathy can follow malnutrition, anemia, or ongoing gut inflammation.

6. Joint and muscle pain. Aching muscles or joints can accompany a heavier inflammatory load.

7. A history of food poisoning. Digestion that has not been the same since a bout of food poisoning is a clue I take seriously.

8. Skin issues. A rash, hives, eczema, or rosacea. Hookworm larvae can cause itching and a localized rash where they enter the skin. Pinworms cause itching around the anus. (3,4)

9. Sleep problems. Trouble falling asleep or waking multiple times. Female pinworms lay eggs at night, which can cause itching and restlessness. (4)

10. Traveler’s diarrhea. International travel plus diarrhea while abroad is a major red flag.

These signs overlap with many gut infections. They do not prove you have worms.

How to Tell the Difference Between Parasites, Candida, and SIBO

Bloating, fatigue, and brain fog can point to several factors in your gut. The exposures differ.

• Intestinal worms and protozoa are usually picked up through contaminated water, undercooked meat, infected soil, travel, or person-to-person contact. Clues include unexplained weight loss, grinding teeth at night, traveler’s diarrhea, and persistent fatigue. (1,2,3,4)

• Candida overgrowth is a yeast imbalance often tied to sugar, stress, or antibiotics. Sugar cravings, skin yeast concerns, and vaginal yeast infections are more typical.

• SIBO happens when bacteria overgrow in your small intestine. Bloating, gas, and distress after certain carbohydrates are common.

The most accurate way to know what you are facing is proper testing, not a guess from a blog list. Work with a practitioner who can order stool testing and, when SIBO is on the table, breath testing.

Parasite Quiz

Used to determine if you need parasite support. Check all that apply to you.

Symptom Checklist:

• I have constipation, diarrhea, or gas
• I have traveled internationally
• I remember getting “traveler’s diarrhea” while outside the country
• I have had a response that I believe was food poisoning and my digestion has not been the same since
• I regularly eat raw fish such as sushi or sashimi
• I have trouble falling asleep and I wake up multiple times during the night
• I have skin irritation in the form of a rash, hives, eczema, or rosacea
• I grind my teeth in my sleep
• I have pain or aching in my muscles or joints
• I feel exhausted, depressed, or apathetic almost all the time
• I never feel satisfied after I eat
• I have iron-deficiency anemia
• I have been diagnosed with irritable bowel syndrome, ulcerative colitis, or Crohn’s disease

Scoring: If you checked 3 or more items, you would benefit from the parasite-support supplements recommended below.

This quiz is a screening tool, not a diagnosis. Persistent, severe, bloody, or dehydrating symptoms, unexplained weight loss, or fever deserve prompt medical care.

Intestinal Parasites, Hashimoto’s, and Graves’

I often saw intestinal parasites in patients with thyroid dysfunction, particularly Hashimoto’s and Graves’. Infections are one of the drivers I address in Pillar IV of The Myers Way®: Heal Your Infections, Relieve Your Stress, and Let Go of Trauma.

Toxoplasma gondii, found in undercooked pork and cat feces, can cause mild flu-like symptoms or none at all. Blastocystis hominis is another organism people pick up more often in developing countries. In my clinic I still recommended testing when autoimmune thyroid patients had gut symptoms that would not resolve.

Supporting your gut does not diagnose or reverse Hashimoto’s or Graves’. Work with your practitioner on supplemental thyroid hormone. Do not start, stop, or change it on your own. For a deeper look at infections and thyroid function, see my book “The Thyroid Connection™.”

How to Test for Intestinal Parasites

The best first test is a stool test, not a blood test. Conventional ova and parasite stool tests look for eggs or a mature parasite under a microscope. They often require three samples. Parasites rotate between dormant and active phases, so a technician may not see a live organism in transit. I often saw false negatives with this method.

In my practice I used a comprehensive stool test with PCR technology to amplify the DNA of an organism. The parasite can be dead or dormant and still be detected.

Giardia is diagnosed with stool samples ordered by a healthcare provider. (2) Pinworm is often checked with a tape test around the anus, because eggs are laid on the skin, not always passed in stool. (4) Ask your practitioner which test matches your symptoms and exposures.

The 3-Step Approach to Solving Parasites

I do not start with random herbs. I use the 3-Step Approach to Solving Parasites: Starve, Disrupt and Kill, Restore and Balance. I never reverse that order. Diet alone is rarely enough to clear an established infection, so a second phase of targeted support is needed.

1. Starve the parasite. Remove sugar in all of its simple forms such as candy, desserts, alcohol, and flours. Limit starchy vegetables and fruit. Limit complex carbohydrates such as grains, beans, fruit, and starchy vegetables to no more than 2 cups per day. Focus on non-starchy vegetables, leafy greens, lean protein, and nourishing fats. Parasites feed on sugar and simple carbohydrates.

2. Disrupt and kill the parasite. Disrupt with Biofilm Disruptor. It is designed to disrupt biofilms and support microbial balance and gut health. Then kill with Microb-Clear® to prune back and promote balance. I discuss Biofilm Disruptor first, then Microb-Clear. Do not skip the disrupt step.

When organisms break down, you may notice headaches, brain fog, nausea, or feelings similar to the flu. People call this die-off. Charcoal Binder Complete can help bind unwanted compounds in your digestive tract so you can eliminate them. Ask your practitioner how a binder fits into your routine.

3. Restore and Balance. Restore with Probiotic 100 Billion. It helps restore good bacteria after gut dysfunction. Then balance with ImmuneIG to add beneficial immunoglobulins and facilitate a healthy inflammatory response. If SIBO is also an issue, Primal Earth Probiotic supports a healthy gut environment without adding to bacterial overgrowth, then follow with ImmuneIG.

Some identified parasites require prescription medication chosen by your practitioner. Supplements support microbial balance. They do not replace antiparasitic medication, diagnosis, or medical care

After that sequence, the Repair Bundle supports digestion and your gut lining. It pairs Complete Enzymes with Leaky Gut Revive®.

If you are used to putting everyone else first, this is your reminder: you are worth the commitment. The Myers Way is a way of life, not an 80/20 diet. Stay with Starve, then Disrupt and Kill, then Restore and Balance. That is how you take back your health. 

No matter what you are working through, the foundation stays the same. My Essential 4 Supplements are the four I believe everyone needs, from 1 to 101 years old: a Complete Multivitamin, Fish Oils / Omega-3, a Multi-Strain Probiotic, and Vitamin D with Vitamin K2. They support a healthy inflammatory response, a healthy gut microbiome, and immune function. If you are following the SIBO protocol above, make your multi-strain probiotic a soil-based one such as Primal Earth Probiotic.

FAQs

• What are the signs of intestinal parasites in humans?
  Signs to watch for include digestive changes (constipation, diarrhea, gas, cramps), never feeling full after meals, iron-deficiency anemia, fatigue, joint or muscle aching, skin irritation, grinding your teeth in your sleep, restless nights, a history of food poisoning, and traveler’s diarrhea. Giardia often causes diarrhea and gas. Pinworms often cause anal itching at night. Hookworms can contribute to anemia. (2,3,4) These signs are not a diagnosis.
• How do you get intestinal parasites?
  You can get them from undercooked meat, raw fish, contaminated produce, untreated water, walking barefoot on contaminated soil, animals, and unwashed hands after using the restroom. (1,2,3,4) Parasites are not only a problem abroad. Household spread, especially with pinworms, is common. (4)
• What causes intestinal parasites?
  Exposure causes intestinal parasites. Animals, food, water, soil, and other people can transmit them. (1) Hookworm larvae can enter through skin that touches contaminated soil. (3) Giardia spreads when you swallow organisms from stool-contaminated water, food, surfaces, or people. (2)
• What are intestinal parasites?
  Intestinal parasites are organisms that live in your intestines and feed off you. They include protozoa such as Giardia and worms such as pinworms, hookworms, roundworms, whipworms, and tapeworms. (2,3,4) Some steal nutrients from your meals. Some feed on blood. Some lay eggs that disrupt sleep.
• How do you get rid of intestinal parasites?
  Work with a qualified practitioner on the right stool test, and use prescription medication when it is indicated. I support the gut with the 3-Step Approach in order: Starve (remove sugar, alcohol, and refined flours; limit complex carbohydrates to no more than 2 cups per day), Disrupt and Kill (Biofilm Disruptor, then Microb-Clear), Restore and Balance (Probiotic 100 Billion, then ImmuneIG; Primal Earth Probiotic if SIBO is also present). Diet and supplements do not replace medical care. Severe, bloody, or dehydrating symptoms need prompt evaluation.

References

1. Centers for Disease Control and Prevention. “What Causes Parasitic Diseases.” CDC, July 12, 2024. www.cdc.gov/parasites/causes/index.html. Accessed on September 10, 2026.

2. Centers for Disease Control and Prevention. “About Giardia Infection.” CDC, May 2, 2024. www.cdc.gov/giardia/about/index.html. Accessed on September 10, 2026.

3. Centers for Disease Control and Prevention. “About Hookworm.” CDC, June 13, 2024. www.cdc.gov/sth/about/hookworm.html. Accessed on September 10, 2026.

4. Centers for Disease Control and Prevention. “About Pinworm Infection.” CDC, September 9, 2024. www.cdc.gov/pinworm/about/index.html. Accessed on September 10, 2026.