My child was bitten by a spider; therefore, we must kill all giraffes. I’m allergic to cats, so any home that has one should be burned down, rebuilt and the builder sued because the cat got in. There’s mold in my bathroom. There’s mold on my child’s toy. Quick, call the feds!  

Stop. Breathe. Don’t kill the giraffes just yet.  

Those examples sound ridiculous, but when it comes to household mold, they’re not far from reality. After all, the mold remediation business continues to grow, the media remains saturated with stories of families forced to leave their homes due to mold growth, and according to the Environmental Protection Agency, September is National Mold Awareness Month.    

Over and over, we hear the same song: Mold is toxic! If it moldy, throw it out! Somebody think of the children! But most molds aren’t making you sick. Molds pose about as much risk to a healthy adult as dirt, unwashed salad mix, or a walk in the woods. There’s always a chance, but that chance is pretty darn slim. So, why the fungal furor?  

Nobody is discounting the scientific studies on the effect of mold exposure on humans, and there are members of the Fungal Kingdom that can cause asthma, allergic rhinitis and other conditions over long-term exposure. 

Black mold, Stachybotrys chartarum, is a well-studied culprit, with known human effects. Because those effects are so irritating, the word “mold” has been separated from the causal organism and turned into a four-letter word. But there are an estimated 1.5 million fungal species on Earth, and around 30,000 “mold” species known (about 2,000 genera). The mold remediation industry generally notes that five of those genera are a problem — that’s 0.25%. 


Here come our giraffes again. Consider the animal kingdom, and just one division: vertebrates. This spans humans, birds, dogs, snakes, etc. The rattlesnake Crotalus cerastes is venomous to humans. This means that all dogs are also dangerous, right? Of course not. We understand the immense variability of the animal kingdom but seem to get bogged down with the fungal kingdom. Just because a fungus looks or acts like a “mold” does not in any way mean that it shares characteristics with a Stachybotrys. In fact, many “molds” are not only useful to humans but are part of human culture.  

Consider, first, cheese and all its wonderful varieties. Blue cheese — a household favorite — gets its color from Penicillium roqueforti. Penicillin was made primarily from Penicillium chrysogenum and P. rubens. Penicillium abounds in the air around us, as do many mold spores, and when it lands on a sufficiently wet and porous surface, secretes a dark green color as it grows. It sporulates copiously and is one of the best known “molds” in the world. It’s also delicious and, arguably, the savior of humanity. 

Consider, next, art. Human art. Wood art. Renaissance masters from the 1400s-1600s created elaborate marquetry works for palaces and churches in Italy, Germany and other areas of Western Europe. A distinctive blue-green color in works from this time came from wood colonized by Chlorociboria species.  

As alchemists and early chemists were unable to fabricate or harvest a similar color, the blue-green of Chlorociboria became worth its weight in gold, and its location in the forests of Western Europe became a heavily guarded guild secret. 

That same fungal color, known as xylindein, is used by scientists today to help make photovoltaic cells for solar panels and batteries. Another mold/wood decay fungus, Scytalidium cuboideum, produces a reddish/blue color that is used for textile dyeing and inkjet printing, and is known for its durability on traditionally hard-to-dye fabrics, like polyester.  

Scytalidium cuboideum is also a common airborne mold, sporulates heavily, and can colonize hair follicles but, sadly, does not give you red hair. Monascus ruber has had its pink/red pigment used for centuries in Asia as a food colorant.  


“Mold” fungi are critical components of human economy, culture and livelihoods. Mold spores are with us all the time, whether in the bathroom or grocery store, and especially when we go for walks in nature. Mold spores are always in your home, even when you can’t see them. It can be irritating when fungi grow inside your home where you don’t want them, but mold spores once grew on a Petri plate where a scientist didn’t want them, and we got penicillin.  

Before you throw out your child’s expensive wood train set or pay thousands of dollars for a company to spray your walls with fancy paint, remember that most “molds” are benign. Take away their water source and they die. The dots of green on your ceiling don’t have to mean anything more than you should probably get your pipes looked at.  

Don’t go and lick an unknown mold, but don’t have a panic attack about it, either. Let’s give those giraffes a chance.