Brown Roll-Rim

Safety first. The brown roll-rim (also called the poison pax) can cause a severe immune reaction that breaks down red blood cells and can damage the kidneys and liver. It can kill. If anyone may have eaten it, or any wild or unknown mushroom, call Poison Help now at 1-800-222-1222 (US), or your local poison centre or emergency number, and do not wait for symptoms. [1][2] Unlike the death cap, symptoms in the published cases began fast, within about 30 minutes to 3 hours of eating. [3][4] Call 911 (US) for collapse, a seizure, trouble breathing or if the person cannot be woken. [2] Tell the doctors exactly which mushroom was eaten: in one fatal case the illness was first treated as amatoxin (death cap type) poisoning. [3] This page gives no identification help, on purpose. See mushroom poisoning: warning signs and urgent help and the mushroom safety quick reference.

The short version. Paxillus involutus is a wild fungus with a long history of being eaten in some places. [3] Toxicologists describe a rare, potentially fatal "Paxillus syndrome": an immune reaction that most often follows repeated eating. [4] It is the opposite of what many people expect: someone can eat it for years without a problem and then react badly. [3][4] No toxin has been identified, and the sources we read describe an immune reaction rather than a classic poison. [3] It is not a food we can recommend, not a supplement and not psychoactive.

Do not identify wild mushrooms from text, photos or apps

Even very experienced gatherers can find it hard to tell whether a mushroom is safe, and a photo or an app cannot replace expert help. [1] The site's safety reference describes a study in which popular identification apps were not reliable enough to exclude poisonous mushrooms. Have any wild-picked mushroom examined by a trained mycologist before anyone eats it. On this site, see cooking edible mushrooms safely.

What goes wrong, and why it is different

• What happens. The proposed explanation is that a substance in the mushroom acts as an antigen: with repeated eating the body makes antibodies, and at a later meal antibody and antigen form immune complexes that stick to red blood cells and destroy them (immune haemolysis). [3] An American toxicology society summary describes the same picture: immune-complex haemolytic anaemia, haemoglobin in the urine, little or no urine, and acute kidney failure from immune-complex kidney inflammation. [4]
• The suspected trigger. The toxicology summary says an allergic response to a protein shared with a Boletus species, called involutin, may start the process. [4] This is a possibility, not a confirmed cause. A 2019 case series states plainly that no toxin has been identified and the mechanism is not confirmed. [3]
• Why prior safe meals mean nothing. In the published fatal cases, a man had eaten the species regularly for about 10 years, and in both cases the people who shared the meal stayed well. [3] A 1986 case report likewise attributes a fatal case to antibodies against the fungus in sensitised people. [5] A 1995 review concludes that eating it is dangerous because of the risk of sensitisation followed by immune haemolytic anaemia. [6]
• Gut upset is separate. Other people get ordinary stomach illness from raw or poorly cooked mushrooms, and the 2019 authors note that similar reactions have also followed proper heating. [3]
• Rare, but not trivial. The 2019 authors found 14 published cases in English and German with 6 deaths, and added two more fatal cases. [3] Reports are case-level, so no rate of illness can be given.

Symptom timeline

In the two fatal 2019 cases the patients (a 46-year-old man and a 32-year-old woman) died about 3 to 5 days after the meal. The woman also had untreated hepatitis C, which the authors say may have added to her illness. [3]

Treatment (what the sources describe)

Treatment is hospital care and is aimed at shock, clotting problems and organ failure. [3] The 2019 authors say that "adequate anti-shock therapy and plasmapheresis" (filtering the blood plasma to remove the antibody complexes) may be essential, but this rests on two cases. [3] In one patient described in 1986, daily plasma exchange lowered free haemoglobin and immune-complex levels by 60 to 75% per session and kidney failure was treated with dialysis; this is a single case, and we read only the abstract. [5] One 2019 patient also received a hydrocortisone dose. [3] The sources we read describe no specific antidote. Do not try home remedies, and do not make the person vomit; follow the poison centre. The NHS (UK) advises against making someone sick and against giving food or drink. [8]

Edible mushrooms it is mixed up with

We found no published poisoning report that names an edible look-alike. In the published cases the mushroom was eaten knowingly as a food, and in one case it was cooked in the same meal as honey fungus and porcini (the authors name Paxillus as the cause). [3] See honey mushroom and porcini. That is naming, not teaching: the safe rule is never to pick wild mushrooms by description.

Lab data and chemistry

Wikidata, the open knowledge base behind the LOTUS natural-products project, lists 19 compounds reported in Paxillus involutus (Q518069). None of the statements in our file has a paper attached. [7] A listing means "reported in at least one study of this species". The compound pages themselves were not opened. None of the entries is shown, in anything we read, to cause the illness.

A. What the laboratory literature reports in this mushroom

B. Measured values. USDA FoodData Central has no entry for this species, and we found no open measured value for any compound above, so none is given and the lab data file is not created for this page.

C. What the numbers do and do not mean

• A listing in Wikidata shows a compound was reported in the species; it gives no amount and no effect on health.


• No toxin has been identified, so no chemical figure can tell whether a given mushroom is dangerous. [3]


• Wikidata describes involutin as a compound; a toxicology summary calls it a protein. We have not resolved this, so treat the involutin link as unconfirmed. [4][7]


• This species has no supplement or health use.

Related pages

• Mushroom poisoning: warning signs and urgent help
• Mushroom safety quick reference
• Cooking edible mushrooms safely
• Death cap
• Plant and mushroom poisoning