Orellanine Mushroom Toxicity

Updated: Aug 21, 2014
  • Author: Reed Brozen, MD; Chief Editor: Asim Tarabar, MD  more...
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Cortinarius orellanus, the poznan cort mushroom, is one of approximately 10 types of mushrooms that can cause fatal poisonings. Thousands of mushroom species are increasingly studied and collected by amateur mushroom hunters. About 100 of these can cause serious illness, but only a handful cause death.

People become sick after ingesting mushrooms for several reasons. They may have ingested toxin-containing mushrooms or mushrooms that cause Antabuse-type reactions to alcohol; they may experience difficulty digesting large amounts of mushrooms or have immunologic reactions to mushroom derived antigens.

Cortinarius species (corts) that may contain the orellanine toxin include the following:

  • C orellanus

  • C speciosissimus

  • C rainierensis

  • C callisteus

  • C gentilis (deadly cort; in Europe, gentle cort)

  • C splendens

  • C cinnamomeus group

  • C semisanguineus group

The most common of these in North America is probably C gentilis, although C orellanus and C speciosissimus are most often implicated in documented exposures. Presence of C orellanus in North America remains unconfirmed.

Orellanine is the major toxin found in these mushrooms. Orellanine (3,3',4,4'-tetrahydroxy-2,2'-bipyridine-1,1'-dioxide) is a colorless, crystalline, nephrotoxic compound. [1] Orelline is a possibly toxic product of orellanine.

Three other polypeptides have been identified: cortinarin A, cortinarin B, and cortinarin C. At least two of those appear to be nephrotoxic in experimental animals.

Mushroom identification is beyond the scope of this text, but existence of corts is one of the many reasons not to eat little brown mushrooms (LBMs).



Patients with orellanine exposure may experience early symptoms because of other components of the mushroom; orellanine appears to be renal specific. Inhibition of alkaline phosphatase decreases production of adenosine triphosphate and disrupts cellular metabolism. Reaction is specific to cells of proximal tubules and seems to cause almost no reaction in glomeruli. Results are tubulointerstitial nephritis and renal failure, with concomitant symptoms and complications.




United States

In 2009, 3 exposures to orellanine-containing mushrooms and no deaths were reported to the American Association of Poison Control Centers' (AAPCC) Toxic Exposure Surveillance System. [2] A range of 0-8 exposures per year have been reported over the past 14 years. The reports by year can be found at the APPC site.

Unknown mushroom type makes up most mushroom exposures each year, usually accounting for well over 80% of mushroom exposures, but deaths in this group remain remarkably low (0-2 per year since 1996).

Another study published in May 2000 used data from the National Center for Health Statistics and found no difference when compared to AAPCC data in numbers of deaths caused by mushroom exposures. [3]


No accurate database exists, but mushroom gathering is more common in Eastern and Western Europe than in North America. Most documented cases of orellanine toxicity are from Europe.


Few data are available to estimate incidence of orellanine poisoning. Most reported cases of renal failure are from Europe. The AAPCC last reported a recognized Cortinarius exposure with a major effect in outcome category (ie, exposure resulted in life-threatening signs or symptoms or resulted in significant residual disability) in 1999. Since 1999 no outcomes have occurred in the major category and only 3 total in the moderate class (ie, signs or symptoms more pronounced, more prolonged, or more systemic in nature than minor symptoms usually indicating the need for some form of treatment, but the patient had no residual disability).