How Long Does It Take for Black Mold to Kill You?

By: Melanie Radzicki McManus & Austin Henderson  | 
black mold on wall
Black mold is a frightening prospect. Regardless of what color it is, you want to remove mold from your house. onebluelight/Getty Images

You don't want mold in your home. Black, green, orange, yellow — no matter the color, it's all undesirable.

Yet, you don't necessarily have to panic if you see it growing on your walls or windowsills. While mold can negatively — and sometimes dramatically — affect your health, it's also possible that you'll suffer no ill effects at all from mold exposure.


But what about black mold? Is it as deadly as people say? And if so, how long does it take for black mold to kill you?

What Is Mold?

Mold is a simple, natural fungus, and guess what? It's everywhere! That's right, from the fresh outdoor breeze to the confines of your cozy living room, mold spores are all around us, all the time.

Mold Facts

  • Mold is a type of fungus.
  • Over 100,000 types of mold exist, with some estimates hinting at millions.
  • Mold spores, those microscopic units, are airborne and omnipresent.
  • Mold gets into homes and buildings through open windows, doors, vents and ductwork. It can also attach itself to your clothes or pets when you're outside, so you inadvertently bring it indoors with you.
  • Once indoors, mold grows wherever there's a lot of moisture (that's something mold and mildew have in common). That's why you'll often see mold around leaky windows or pipes, or on drywall after flooding.


All About Black Mold (and Its Reputed Infamy)

A notorious reputation precedes "black mold," or its more terrifying name, "toxic black mold." Many are quick to ask, "Can black mold kill you?"

When most people shudder at "black mold", they're usually thinking of Stachybotrys chartarum, a greenish-black mold. Yes, it sounds villainous, but the truth isn't so black and white. Research has linked it to serious health problems like mycotoxicosis (mold poisoning). Yet, science still debates its potency.


For instance, a 2017 report published in Clinical Reviews in Allergy & Immunology challenges the fear, stating no firm evidence ties visible mold exposure, especially black mold, to vague symptoms like memory loss or serious health problems such as infant pulmonary hemorrhage.

Everyone reacts differently to mold. Exposure might be harmless for some, but for others — especially those with mold allergies, asthma, preexisting lung conditions or a compromised immune system — it can spell trouble.

In fact, certain people with these conditions might experience symptoms ranging from runny noses to breathing difficulties after black mold exposure.


The Effects of Mold on Human Health

Mold allergy sufferers might display a runny nose, skin rashes, sinusitis and other allergy symptoms. Those with a weakened immune system could face fungal infections, while respiratory problems might haunt others.

For example, Marie Sterling (not her real name) has been struggling with health issues for 14 years since coming in contact with mold. Despite seeing some of the nation's top mold doctors, her health has never been the same. "I am still permanently sick," she says. "Mold is the worst."


Mold Removal and Prevention

Spotting mold is typically easy — it's either visible on your surfaces or that musty smell gives it away. But here’s the good news: You often don’t need a professional to evict it.

Anti-mold Housekeeping Tips

  • For small areas, scrub moldy surfaces with a commercial product or a mix of bleach (1 cup or 237 mL) and water (1 gallon or 3.8 L).
  • Large infestations (more than 10 square feet or 0.9 square meters) might require professional mold removal.
  • Prevent mold growth by promptly addressing water leaks and ensuring good ventilation.

Your best defense? Keep things dry. Dry homes discourage mold growth. Ensure bathrooms, laundry rooms, and kitchens are well ventilated, use air conditioners and dehumidifiers during humid months, and avoid carpeting moisture-prone areas.


This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.


Frequently Answered Questions

How harmful is black mold?
Black mold spores can cause respiratory and other health issues upon prolonged exposure.
How long does it take for black mold to kill you?
While black mold can cause health problems, there isn't definitive evidence to suggest it can directly cause fatality.