Which Mushrooms Bruise Blue?

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Key Takeaways:

  • Blue bruising in mushrooms may indicate the presence of psilocybin and psilocin.
  • Not all blue-bruising mushrooms are psychoactive. Some non-psychoactive mushrooms also bruise blue.
  • Common blue-bruising mushrooms include Psilocybe cubensis, Psilocybe azurescens, Psilocybe semilanceata, and Boletus campestris.
  • The bluing reaction occurs due to oxidation of psilocin and other compounds when the mushroom tissue is damaged.
  • Blue bruising can help identify magic mushrooms, but chemical testing is needed to confirm psychoactive compounds.


Which Mushrooms Bruise Blue?

Blue bruising is a distinctive characteristic seen in some species of mushrooms. When the flesh of these mushrooms is squeezed, cut or otherwise damaged, blue-colored spots or blotches develop on the injured areas. This bluing reaction has long fascinated mycologists and mushroom hunters alike. But why do some mushrooms turn blue when handled? And can the presence of blue bruising reliably determine whether a mushroom is hallucinogenic? This article will provide a comprehensive overview explaining which mushrooms display blue bruising and the significance of this peculiar phenomenon.

Understanding blue bruising in mushrooms is valuable for both scientific and practical reasons. Mycologists study this trait to better classify and identify different fungal species. Foragers use it as one clue in the search for psychoactive mushrooms. However, while blue bruising can signal the possibility of mind-altering compounds, chemical tests are needed to confirm a mushroom’s activity. As we will see, some harmless mushrooms also turn blue when damaged. After reading this guide, you will understand the mechanisms behind blue staining and have increased knowledge about which mushrooms demonstrate this reaction.

What Causes Blue Bruising in Mushrooms?

Why Do Some Mushrooms Turn Blue When Handled?

Which Mushrooms Bruise Blue?

When you squeeze, cut or otherwise damage the flesh of certain mushrooms, you may notice blue or bluish-green spots appear around the injured areas. This is caused by a chemical reaction within the mushroom. Let’s take a closer look at how this “bluing” effect happens:

Oxidation of Psilocin

Many blue-bruising mushrooms contain the chemical compound psilocin. When a mushroom’s tissues are damaged and exposed to oxygen, psilocin rapidly oxidizes and turns blue. This is similar to how a sliced apple will brown when left out in the air.

Mixing of Chemical Compounds

Some research also indicates that blue bruising involves the mixing and bonding of psilocin with other molecules naturally present in mushrooms. These include various polymers and antioxidant compounds like polyphenols.

Activation of Enzymes

Tissue damage may activate enzymes like peroxidase and polyphenol oxidase that contribute to the oxidation and polymerization reactions behind blue spotting.

So in summary, blue bruising arises from oxidation and chemical interactions when psilocin and other compounds are exposed to oxygen. This causes the color change seen on damaged mushroom flesh.

Do All Blue-Bruising Mushrooms Contain Psilocybin?

Psilocin is the compound directly responsible for blue bruising in most cases. Psilocin is produced when the body metabolizes psilocybin, the psychoactive substance found in “magic mushrooms.” Therefore, blue bruising is considered a possible indicator that a mushroom may contain psilocybin and have hallucinogenic properties.

However, some non-psychoactive mushrooms also occasionally bruise blueish. The reasons for this are not fully understood. One theory suggests oxidized polyphenol compounds may contribute to blue coloration in some mushrooms without psilocybin. So blue bruising alone does not definitively confirm psychoactivity. Chemical testing is required to positively identify psilocybin/psilocin content in mushrooms.

Common Blue-Bruising Mushrooms

Psilocybe Cubensis

The most well-known blue-bruising mushroom is Psilocybe cubensis, aka the “gold cap” mushroom. This species contains significant levels of psilocybin and psilocin and is responsible for the hallucinogenic effects of magic mushrooms. When handled, the stems and caps of P. cubensis quickly develop blue-green discoloration where damaged. It has a cosmopolitan distribution and can be found growing in the wild in many tropical and sub-tropical areas. Due to its potency and the distinct bluing reaction, P. cubensis is one of the easiest magic mushrooms to identify.

Psilocybe Azurescens

Psilocybe azurescens is a potent psychedelic mushroom native to the West Coast of the United States. Called “flying saucers,” these mushrooms grow on wood chips and quickly stain blue when the skin of the cap or stem is bruised. Along with its bluing reaction, P. azurescens can be identified by its habitat and speckled white stem. It contains up to 1.8% psilocybin and 0.5% psilocin and is considered one of the most potent psilocybin-containing mushrooms.

Psilocybe Semilanceata

Psilocybe semilanceata, or “liberty caps,” commonly grow in fields and grasslands. When fresh, they are small and have a conical, bell-shaped cap. This mushroom displays a distinctive blue bruising reaction along the cap and stem when handled. It is one of the most widespread psilocybin-containing species, especially prevalent in Europe, and has long been traditionally used for its psychoactive effects.

Boletus campestris

Boletus campestris is a mushroom known for staining blue when damaged, yet this species does not contain psilocybin or psilocin. It grows in fields and grassy areas and has a stocky brown stem and convex cap. This edible mushroom turns blue-green especially at the stem base when handled. While not psychoactive, its bluing reaction demonstrates that some harmless mushrooms also display this characteristic.

Other Psilocybin Mushrooms

In addition to the major species above, many other psilocybin-containing mushrooms demonstrate some degree of blue bruising, including:

  • Psilocybe cyanescens
  • Psilocybe tampanensis
  • Psilocybe mexicana
  • Psilocybe caerulipes
  • Psilocybe ovoideocystidiata
  • Psilocybe subaeruginascens

However, the degree of bluing can vary considerably between different species and specimens. Some magic mushrooms show only faint blue bruising while others exhibit dramatic, deep blue staining when damaged even slightly.

Significance of Blue Bruising

Does Blue Bruising Indicate Psychoactive Mushrooms?

Blue bruising is strongly associated with the presence of psilocin and psilocybin in mushrooms. Therefore, mycologists and foragers often use this as one identifying characteristic for potentially psychoactive species. However, some non-hallucinogenic mushrooms occasionally demonstrate blue staining as well.

While an important clue, blue bruising alone does not prove a mushroom is psychedelic. Proper identification should rely on an analysis of macroscopic and microscopic features along with chemical testing to confirm psilocybin content.

Using Blue Bruising to Help Identify Magic Mushrooms

Looking for blue bruising can be helpful to narrow down the search when identifying hallucinogenic mushrooms. For urban foragers or mycologists surveying an area, detecting blue staining provides a quick way to spot mushrooms that merit further investigation. The mushroom can then be examined for other features suggestive of psilocybin content.

Blue bruising is most useful for identification when considered together with other characteristics like spore print color, habitat, physical structure and microscopic details. For example, bruising coupled with a dark purple-brown spore print points toward species like Psilocybe cubensis and P. cyanescens.

Does More Blue Bruising Indicate Higher Potency?

Some sources claim that more extensive blue bruising corresponds to higher psilocybin levels in a mushroom. However, studies have not found a consistent correlation between degree of staining and psychoactive potency. Light and heavy bruising can both occur in mushrooms with high psilocybin content.

While staining intensity can vary, the location of bruising does seem meaningful. According to some research, bruising concentrated at the base of the stem indicates higher psilocin levels throughout the mushroom. Caps that stain blue also signal a more potent specimen. But overall intensity does not definitively reveal potency.

Risks of Eating Blue-Bruising Mushrooms

Finding a blue-staining mushroom in the wild does not guarantee it is safe to consume. Some mushrooms with bluing reactions contain deadly toxins or have poisonous lookalikes. Consuming a wild mushroom without proper identification and expertise can be extremely dangerous.

Even known psychoactive mushrooms like Psilocybe cubensis can be hazardous if eaten raw, in excess, or without oversight. Psilocybin and psilocin produce powerful hallucinogenic effects and mental side effects that require care in usage. Never ingest a blue-bruising mushroom unless you are 100% certain of the species and effects.

How to Safely Pick and Identify Psychoactive Mushrooms

Searching for psilocybin mushrooms in the wild requires diligent study and extreme caution. Here are some best practices for evaluating blue-bruising mushrooms:

  • Thoroughly research known psychedelic species in your region and learn how to positively identify them. Consider enrolling in a mycology course.
  • Carefully assess all macroscopic and microscopic morphology, including features beyond blue staining. Take high quality photos of all parts.
  • Note key habitat characteristics like substrate, elevation, seasonality and associated plants/trees.
  • Take a spore print and assess color and texture. Purple-brown hints toward psilocybin presence.
  • Consider getting a psilocybin test kit to chemically analyze mushroom samples.
  • If consuming, start with a small dose to assess potency and individual reaction.
  • Pick sustainably in permitted areas without overharvesting fruiting bodies.

Proper mushroom identification requires a holistic analysis of multiple attributes. While an important diagnostic feature, blue bruising alone does not confirm a mushroom’s safety or psychoactivity. Exercise great care when wild foraging for mushrooms of any kind.

FAQs About Blue-Bruising Mushrooms

Why do some mushrooms bruise blue while others do not?

Blue bruising results from the oxidation of psilocin and other compounds when the mushroom tissue is damaged and exposed to air. Mushrooms that lack psilocin and similar chemicals do not exhibit this bluing reaction when handled.

What causes blue bruising in boletes like Boletus campestris?

The bluing reaction seen in some boletes is not fully understood. It may be due to the oxidation of polyphenolic compounds rather than psilocin since boletes do not contain psilocybin. The specific enzymes and chemical pathways behind bruising are still being investigated.

Can you eat a mushroom that bruises blue?

Some blue staining mushrooms are edible, like Boletus campestris. However most blue-bruising mushrooms contain psilocybin/psilocin and have psychoactive effects if consumed. Never eat a wild mushroom unless you have identified the exact species and confirmed it is safe to ingest.

Do all parts of a mushroom bruise blue or just the stem and cap?

The blue bruising reaction can occur in any fleshy mushroom tissue when injured. Caps, stems and gills frequently show blue spots. Bruising sometimes occurs on the undersurface of caps in species like Psilocybe cubensis. The interior flesh of mushroom stipes also often stain blue when revealed.

Does blue bruising happen immediately or develop over time?

In mushrooms containing psilocin, blue staining typically begins within a few minutes after damage occurs. The bluing reaction can continue to intensify and spread over the next several hours as enzymes and compounds diffuse through surrounding tissue. Bruising usually completes within 24 hours.


The development of blue or blue-green spots on a mushroom after handling is a trait seen in numerous fungi. This bluing reaction arises from the oxidation of psilocin and other chemical compounds when exposed to air. While strongly associated with psilocybin-containing psychoactive mushrooms, some non-hallucinogenic species also occasionally display bruising. Blue staining can serve as a useful identifier but requires support from microscopic and macroscopic morphology, chemical testing, and understanding of habitat and range to conclusively identify a mushroom species. By learning proper identification techniques, foragers can more safely evaluate bluing mushrooms for their edibility and possible psychoactivity. With the information provided in this guide, you now have an extensive understanding of the causes, meanings and cautions associated with spotting blue bruises on wild mushrooms

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