How Toxic Mold Exposure Harms the Body

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Toxic mold can cause some serious health problems. Before pulling out a natural cleaner to tackle that black mold you found in your home, it’s important to consider a few things first.

There are different kinds of indoor mold, some more harmful than others. You need to learn how to tell if mold is toxic and what to do if it is. Plus, it’s important to know the health risks of living in a house that is plagued with a mold problem.

What Is Mold?

Mold is a type of fungi that grows on surfaces, whether it’s the food at the back of your fridge or that damp wall in your basement. Mold grows in response to humidity and temperature, as a natural part of decay. There are thousands of varieties of mold on the planet.

Some types of mold can facilitate the natural breakdown of material, while other types can be harmful to human health. What makes the difference between “normal” mold and the kind that results in mold toxicity? Harmful molds can cause mold allergy, toxicity, or pathogenic infections.

Some kinds of harmful molds you might find in your home include:

  • Acremonium: a toxic mold that is often located inside humidifiers or behind window seals
  • Mucor: an allergenic mold that grows near condensation from air conditioner units or HVAC systems
  • Alternaria: a common type of mold that causes allergies, typically found in showers or bathtubs
  • Cladosporium: a common type of allergenic mold found on home surfaces like carpets, draperies, or fabrics
  • Fusarium: a toxic mold that grows in homes that experience water damage
  • Stachybotrys: also known as “black mold;” a toxic type that grows in homes around moisture or condensation, like damp basements or places water has leaked
  • Ulocladium: a toxic mold that looks black, but is not “black mold;” found in areas where wetness collects, like poorly sealed windows, bathrooms, laundry rooms, or basements

The Centers for Disease Control and Prevention (CDC) says that it’s not necessary to determine the kind or type of mold that’s found in your home. If you have any mold, you should take care of it with proper precautions and understanding that exposure may lead to health risks.

What Causes Toxic Mold?

There are always small amounts of mold everywhere. It exists in the air and on normal surfaces. Mold growth that takes off is caused by moisture.

Leaky sinks, damaged window seals, and cracked shower seals are common ways for mold to develop—and it happens quickly. It only takes a few days of the right conditions (often moisture and humidity) for mold to grow.

Here are some of the most common places that mold can be found in a home:

  • Kitchen, bathroom, laundry room and basements
  • Attic or top level of a home due to roof leaks
  • Drywall, wood, and other porous construction surfaces
  • Crawlspaces
  • Carpet padding
  • Water tank heater
  • Air conditioner unit or HVAC system

Not all mold from these sources will be toxic, but all mold can lead to allergies or irritation to some degree if it is breathed in.

You can’t control the type of mold that grows in a specific area, and whether it is toxic, allergenic, or pathogenic, it’s all bad for health. Ensuring that there is no situation ripe for potential is the best way to prevent toxic mold.

Toxic black mold is incredibly common, and more of a problem than most realize. In the 1990s, the Environmental Protection Agency ran a study that tested 100 office buildings for water damage. The results found that 43 percent had current water damage and 85 percent had water damage in the past. Any past or present water damage can lead to perfect conditions for mold replication.

How Does Toxic Black Mold Affect the Body?

Although scientific research is plentiful and increasing, mold-induced symptoms are often misdiagnosed. The most frequent mold-related symptoms are respiratory, particularly allergies and asthma.

The symptoms of mold exposure vary greatly because your individual genetics play a role in how you’ll react if exposed.

Symptoms of Toxic Mold Exposure

The exact symptoms depend on the person, length of exposure, and types of mold. Because everyone is genetically unique, and other chemical or toxin exposures may be present along with black mold (such as other fungi or bacteria, formaldehyde, ozone, and so on), it’s difficult to attribute every symptom to black mold alone.

Mycotoxins and black mold can cause issues on their own, or they can worsen existing conditions that you may have. This is why it can be challenging to get a diagnosis.

However, research has found some potential links between the following symptoms and black mold exposure.

Lungs and Respiratory

  • Respiratory symptoms like coughing, wheezing, congestion, runny nose, hay fever, or shortness of breath are commonly associated with mold exposure of all types. Genetically predisposed people will experience worse responses.

Brain, Cognitive, and Neurological

  • Cognitive symptoms like memory problems, or worsening Alzheimer’s or dementia, has been associated with mold exposure by some researchers, as explained in a 2016 article in Aging.
  • Exacerbated problems with neurological conditions like autism spectrum disorder and mycotoxins have been studied without definitive answers. A 2017 study suggests a link, but a 2016 study found no association. Both conclude that more research needs to be done to understand how mycotoxins affect neurological health, especially in children.
  • A 2019 study from Toxicological Research links headaches with mycotoxin exposure.

Systemic and Cellular

  • Myalgic encephalomyelitis, sometimes referred to as Chronic Fatigue Syndrome, has a strong association with mycotoxins and toxic mold exposure. A 2013 study found that 93 percent of those with chronic fatigue tested positive for mycotoxins as compared to 0 percent of the control group.
  • The thyroid regulates energy and metabolism, and mold or mycotoxin exposure can produce hypothyroid and low-energy symptoms in a condition known as non-thyroidal illness syndrome.


  • Vomiting, diarrhea, and abdominal pain are digestive symptoms linked with mycotoxin exposure.
  • Mold can suppress the body and increase the chance for a secondary opportunistic infection, like Candida yeast overgrowth.

Keep in mind that these symptoms can be attributed to numerous other conditions or health problems, so it’s important to work with your medical provider to find answers unique to your situation. But if you have symptoms that repeatedly have no explanation, it’s time to dig deeper.

If you suspect that your home or workplace may have current or previous water damage or mold exposure, it’s important to mention this to your doctor. The longer you live or work around toxic mold, the more serious your symptoms can become.

How to Test for Toxic Mold

You can’t tell if mold is toxic just by looking at it. The best way to test depends on how much mold is visible and how much you’re concerned that mold could be impacting yours or your family’s health.

Mold spores can be on surfaces, in the air, or both, and getting answers is the only way to know what you’re dealing with. Here are a few tests you can do yourself:

  • ERMI test: This is the mother of all mold tests and can tell the mold history of a home. This will show the type of mold, including species (like Aspergillus), genus (Aspergillus alternate), and the number of spores. This information is helpful to know which treatment someone needs and what type of remediation needs to be done. An ERMI test identifies 36 different types of toxic mold.
  • HERTSMI test: This is the cheaper version of an ERMI test. It will still give both mold genus and species, but it only tests for 5 of the most common toxic molds.
  • Mold detection kit: These at-home kits will allow you to sample up to 9 different locations in the home. Results will report the type of mold growing in each area.
  • Dust test: This podcast episode goes into the details of the test and next steps with any mold problem.

If the problem is really bad, hiring a professional mold inspector to do a comprehensive review is the best way to ensure your family’s safety. Learn more from podcast guest Dr. Tim Jackson on Mold Toxicity, Testing, and Remediation.

What to Do After Toxic Black Mold Exposure

If you get the bad news that you have black mold in your home, don’t panic! While it’s not the answer anyone wants, the best thing to do is to get the situation handled by a mold remediation professional.

While hiring a professional is certainly more expensive than DIY mold removal, you don’t want to skimp on this. Having a professional remediate your mold is important because all porous materials need to be removed from the area and properly disposed of. If not, you’ll have another mold problem before long.

Experienced remediators should handle mold infestations and mold removal. Not all certifications and training are equal. Hire remediators with an IICRC certification.

Professionals should wear sufficient protective equipment and isolate the contaminated area. If someone shows up in a paper mask with a bottle of bleach, those are big red flags!

Mold Cleaners: Do They Work?

Most mold cleaners sold in stores only bleach the mold so that it’s no longer visible. But the mold roots are still there and spreading underneath the surface. This is why it’s important to follow this advice when it comes to mold in your home:

  • Do NOT try to clean a mold infestation yourself! This will spread the spores and further contaminate the area. At best, messing with mold can give someone some sinus issues.
  • Do NOT use bleach to clean mold. Even though this advice is rampant on the internet, bleach won’t kill mold, and the moisture can feed mold growth on porous surfaces. The Environmental Protection Agency does not recommend bleach for mold.
  • Sanitizing cleaners that will remediate mold from personal, non-porous items include Moldex and other EPA-approved products. For those sensitive to chemicals or strong fumes, tea tree oil also works.
  • Unfortunately, if you’ve had mold in your home, you may have to throw away certain porous items that have been contaminated. Paper, leather, and plastics can’t be properly sanitized after mold exposure and could continue to spread it.

If non-porous items have been in contact with mold, be sure to use a cleaner that will destroy the mold and mycotoxins, under professional advice.

Keeping Toxic Mold Away

Reading about toxic mold can suddenly make you think it’s everywhere. But you can be proactive about keeping mold out of your living space. However, these will only work if you don’t currently have a mold problem. They won’t work to remove current moldy situations.

Air Purifiers for Mold

Air purifiers help keep the air clean in your home to limit toxin exposure. Look for an air purifier that’s able to filter out mycotoxins, which range from 0.3 to 0.03 microns in size. In comparison, a single human hair is between 50 to 75 microns across.

Air purifying plants, like gerbera daisy and peace lily, can also help. Be careful with indoor plants though, since damp indoor soil is prone to mold and mildew growth. The top 10 best air purifying plants, according to Environmental Health Perspectives, are:

  • Areca palm
  • Lady palm
  • Bamboo palm
  • Rubber plant
  • Dracaena
  • English ivy
  • Dwarf date palm
  • Ficus
  • Boston fern
  • Peace lily

Cleaning for Mold Prevention

Areas that are more prone to mold and mildew should be cleaned more often. Bathrooms, kitchens, and anywhere else in the home where water could collect are the important spots to watch.

If you’re like me, you don’t love cleaning the bathroom, but the right cleaners can make all the difference. Natural antifungal cleaners like tea tree oil and clove oil work well without toxic fumes.

Homebiotic, which is a probiotic for the home, also helps create an environment hostile to harmful microbes. Use these products regularly to prevent mold growth, not to clean a mold infestation!

Preventing Moisture and Mold Growth in the Home

High moisture levels are mold’s best friend. Here are some ways to prevent dampness in the home.

  • A dehumidifier can help keep moisture levels down. Be sure to clean it regularly as a dehumidifier with unemptied water can be a mold source! Use this in a basement or anywhere that tends to be damp or at-risk for mold growth.
  • Make sure that areas get dried out properly after use. Wipe down kitchen, bathroom, and laundry surfaces after use and always address spills.
  • Having a working vent fan in the bathroom, that everyone remembers to use, prevents a perpetually damp environment. Vents should be used during and showers and baths, until moisture has dried up.
  • Check under and behind sinks for signs of leaks and promptly fix any that develop.
  • Check windows for leaks.

This article was medically reviewed by Dr. Robert Galamaga, whois a board-certified internal medicine physician. As always, this is not personal medical advice and we recommend that you talk with your doctor or work with a doctor at SteadyMD.

Have you ever had mold in your home? Did you notice any negative health effects from it?

  1. ScienceDaily. (n.d.). Mold.
  2. Centers for Disease Control and Prevention. (2019). Facts about Stachybotrys chartarum.
  3. Centers for Disease Control and Prevention. (2020). Basic facts about mold and dampness.
  4. Mendell, M.J. (2005). Indoor environments and occupants’ health: What do we know?
  5. World Health Organization. (2018). Mycotoxins.
  6. Centers for Disease Control and Prevention. (2018). Case definition: Trichothecene mycotoxin.
  7. Omotayo, O. P., Omotayo, A. O., Mwanza, M., & Babalola, O. O. (2019). Prevalence of Mycotoxins and Their Consequences on Human Health.
  8. United States Environmental Protection Agency. (n.d.). Mold and health.
  9. Kuhn, D. M., & Ghannoum, M. A. (2003). Indoor mold, toxigenic fungi, and Stachybotrys chartarum: infectious disease perspective.
  10. Mayo Clinic. (2019). Mold allergy.
  11. Bredesen D. E. (2016). Inhalational Alzheimer’s disease: an unrecognized – and treatable – epidemic.
  12. De Santis, B. et al (2017). Study on the Association among Mycotoxins and other Variables in Children with Autism.
  13. Duringer, J., Fombonne, E., & Craig, M. (2016). No Association between Mycotoxin Exposure and Autism: A Pilot Case-Control Study in School-Aged Children.
  14. Brewer, J. H., Thrasher, J. D., Straus, D. C., Madison, R. A., & Hooper, D. (2013). Detection of mycotoxins in patients with chronic fatigue syndrome.
  15. Somppi T. L. (2017). Non-Thyroidal Illness Syndrome in Patients Exposed to Indoor Air Dampness Microbiota Treated Successfully with Triiodothyronine.
  16. Kuhn, D. M., & Ghannoum, M. A. (2003). Indoor mold, toxigenic fungi, and Stachybotrys chartarum: infectious disease perspective.
  17. United States Environmental Protection Agency. (n.d.). Should I use bleach to clean up mold?
  18. Claudio L. (2011). Planting healthier indoor air.
Katie Wells Avatar

About Katie Wells

Katie Wells, CTNC, MCHC, Founder of Wellness Mama and Co-founder of Wellnesse, has a background in research, journalism, and nutrition. As a mom of six, she turned to research and took health into her own hands to find answers to her health problems. is the culmination of her thousands of hours of research and all posts are medically reviewed and verified by the Wellness Mama research team. Katie is also the author of the bestselling books The Wellness Mama Cookbook and The Wellness Mama 5-Step Lifestyle Detox.


5 responses to “How Toxic Mold Exposure Harms the Body”

  1. Jackie Avatar

    Thanks so much for sharing this info about mold! I have been suspicious of mold in my home & I think I am going to go ahead with a mold inspection Wish me luck haha!

  2. Jen Stout Avatar
    Jen Stout

    Fantastic and very informative article, Katie! I lived in an apartment full of Stachybotris, an especially toxic black mold, for years before knowing, while attending grad school at SMU. Went from super healthy to the sickest of the sick — like lost all the hair on my head sick! I set out to build my first healthy home years ago, using all non toxic materials, and have since started my own healthy home building company with my builder hubby in Central Texas. Improvement and change are long overdue in the construction industry! …Thanks again for the informative post about the dangers of indoor mold.

    1. Lauren Avatar

      Hi Jen!
      I’m so interested about your nontoxic construction company. We are about to build a home (currently living in an RV and we just found mold! Having lots of health issues!)
      We have always used non toxic paints/sealants/furniture/insulation etc. and plan on making this home as non toxic as possible. Hiring someone to consult us along the way would be great!

  3. Tayler Beck Avatar
    Tayler Beck

    Do you have any advise/suggestions for families who can’t afford a mold remediation specialist?

    1. Jamie Larrison Avatar

      It depends on the situation, where the mold is, and how much it’s affecting the people living there, but for our family it was healthier, easier, and cheaper to move to a clean house.

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