Facts About Oyster Mushrooms


Use caution if trying them for the first time. Some people show an allergic reaction to their spores while others may experience an upset stomach. Try a small amount first to see how your body reacts.  

Always wash mushrooms before using.

The oyster mushroom is a saprotroph, meaning it feeds on dead and decaying matter (mainly wood).

They are found on hardwoods throughout the world in the spring and fall.

The caps usually range between 5 to 25 cm (2 to 10 inches) and are shaped like a fan or an oyster. The caps are rolled into a convex shape when young and will flatten out and turn up as the mushroom ages. They can be white, yellow, brown, tan, and even pink!

They have a unique scent that is often described as sweet like anise or licorice (liquorice).

The latin name Pleurotus ostreatus means "sideways oyster", referring to the oyster-like shape of the mushroom.

There are a few closely related species that can be hard to distinguish from oysters. Thus it's helpful to bring someone knowledgeable when searching for them in the woods.

The mycelia will kill and eat nematodes (small roundworms) and bacteria, making them one of the few carnivorous mushrooms

Cleaning up the Environment

I believe the most fascinating use of these mushrooms is their growing role in mycorestoration. Mycorestoration is the process of using mushrooms to decrease pollution levels in a given area.

Oyster mycelium is ravenous! It will eat through wood, paper, coffee grounds, and even petroleum products. Why will it decompose all these materials?

These mushrooms are found on hardwoods. They secrete enzymes that break down the organic bonds in wood into smaller molecules. The carbon-hydrogen bonds in wood are similar to those found in oil and pesticides. Thus due to their love of wood, oysters are also efficient in breaking down the organic bonds in toxic chemicals.

Imagine oil spills and pollution someday being decreased by mushrooms. This is the subject of numerous studies in polluted areas. One experiment is currently being performed by Matter of Trust, a non-profit group in San Francisco.

In Nov07 the freighter Cosco Busan spilled 58,000 gallons of bunker fuel into San Francisco bay. Matter of Trust has partnered with famous mycologists to see if some of the spilled fuel can be removed by oyster mushrooms. Read about this fascinating ongoing experiment (and its political hurdles) here.

In addition to breaking down the organic bonds in oil, oyster mushrooms are also powerful absorbers of mercury. Their mycelium channels mercury from the ground up into the mushroom itself. Once the mushroom is picked and destroyed (obviously you wouldn't want to eat it!), the mercury is removed from the environment.

Heavy metal pollution is a serious problem all over the world. Just this morning (Aug08) I read an article about high mercury levels in the Great Salt Lake in Utah. What if someday we were able to remove toxic heavy metals like mercury from our soil and water by cultivating mushrooms?

Is it possible? Can we remedy some of the terrible damage we've done to the environment through mushrooms? Plenty seem to think so. If mycorestoration is the wave of the future, oyster mushrooms will be leading the way!

Medicinal Oysters: Cancer and Cholesterol

In addition to helping the environment, oyster mushrooms can help your body as well! So far they seem to have the most promising effect on cholesterol levels and cancer.

Oysters naturally produce compounds called statins. Statin drugs reduce "bad cholesterol" (LDL) by stimulating receptors in the liver to clear the cholesterol from the body.

Studies have shown a link between consuming Pleurotus ostreatus and a lowering of cholesterol levels, no doubt due to the statins they produce. Hopefully future research will reveal exactly how much to eat to get these effects.

As for cancer, research shows a possible anti-tumor effect from polysaccharides in oysters. A polysaccharide is a complex carbohydrate made up of smaller sugar molecules.

Specific polysaccharides, known as beta-D-glucans, are suspected to stimulate the immune system to fight cancer.The

beta-D-glucan isolated from oyster mushrooms is called pleuran.

Studies are ongoing into the effects of pleuran for cancer treatment. Eventually I'd like to link to a legitimate human trial, as all those I've found so far have used laboratory animals.- Source - Mushroom Appreciation page

Use caution if trying them for the first time. Some people are allergic to their spores while others may experience an upset stomach. Try a small amount first to see how your body reacts.