Black Mushroom Poisonous? Which Black Fungi Are Toxic

Some black mushrooms are poisonous and some are not, and the black colour itself tells you nothing about which is which. The California Poison Control System lists "poisonous mushrooms are brightly colored" and "white mushrooms are safe" among its common myths: toxic species come in every colour, and the deadliest North American mushrooms are white, green-tinged or tan rather than black.

What black does tell you is which group to look in. Mushrooms end up black in four ways, and each group has its own risks:

• They turn black as they age. Inky caps dissolve into black liquid. One of them, the common ink cap, causes a reaction with alcohol.
• They stain black when cut or bruised. Blackening brittlegills and the black-staining polypore. This group includes the most dangerous black mushroom on this page, Russula subnigricans.
• They are black or near-black from the start. Black trumpets, black morels, dead man's fingers, King Alfred's cakes, black witches' butter and black earth tongues.
• They are sold dried as "black mushroom". Shiitake and wood ear. Both are cultivated foods, and each has a documented way of making people ill.

The sections below take each group in turn. If someone has already eaten a black mushroom, skip ahead: call Poison Control at 1-800-222-1222 now, before symptoms start.

These are the black mushrooms people most often find, with the feature that separates each one:

• Shaggy mane (Coprinus comatus) and common ink cap (Coprinopsis atramentaria). White or grey at first, then blackening from the cap edge inward until they drip black liquid. Found in lawns and disturbed ground. Details on black mushrooms in yard.
• Black trumpet (Craterellus cornucopioides). Dark brown to black, shaped like a vase or trumpet with a wavy edge, 1 to 5½ inches tall, with no true gills underneath, only a smooth to slightly veined surface. The Missouri Department of Conservation (MDC) records it in clusters on mossy hillsides in deciduous forest, June to September.
• Black morel (Morchella angusticeps). Black to brownish-black ridges with yellowish-brown pits, completely hollow inside, April and early May under ash, tulip poplar, oak and hickory, and on burned ground (MDC). See morel identification.
• Dead man's fingers (Xylaria polymorpha). Black, club- or finger-shaped with a wrinkled charcoal-like surface and tough whitish flesh, ½ to 3 inches tall, in clusters at the base of rotting hardwood stumps (MDC).
• King Alfred's cakes (Daldinia concentrica). Hard, shiny black half-balls 2 to 7 cm wide on dead wood, with concentric rings inside when cut (Wikipedia).
• Black witches' butter (Exidia glandulosa). A dark, rubbery, jelly-like blob up to 5 cm across on dead broadleaf branches, especially oak (Wikipedia).
• Black earth tongues (Trichoglossum hirsutum and relatives). Black-to-dark-brown clubs up to 9 cm tall standing in old grassland (Wikipedia).
• Blackening brittlegills (Russula nigricans and relatives). Large cap mushrooms whose flesh reddens and then turns black after cutting. The deadly Russula subnigricans belongs here.
• Black-staining polypore (Meripilus sumstinei). A rosette of greyish-yellow fan-shaped caps up to 32 inches across at the base of oaks, bruising black wherever touched (MDC).

Russula subnigricans is the black-staining mushroom with the most serious documented poisonings. Its name means "false blackening russula". Wikipedia records it in East Asia, with poisonings in Taiwan and Japan, and describes its toxic effect as rhabdomyolysis, the breakdown of muscle tissue.

The largest case series we found is a retrospective study in Frontiers in Toxicology (2026) of 103 patients treated at the Affiliated Hospital of Yunnan University between January 2020 and December 2024:

• 12 patients died, a mortality rate of 11.7%.
• Symptoms began early, with a median of 2.4 hours after eating, and 81.6% of patients had symptoms within 6 hours. An early start does not mean a mild poisoning with this species.
• Nausea or vomiting affected 85.4% of patients and muscle pain 52.4%. ECG changes appeared in 65.1%, and signs of liver injury in 97.1%.

The detail that matters for anyone looking at a black-staining mushroom is the colour change. Wikipedia notes that when Russula subnigricans is cut, its flesh turns pale red but does not go on to turn black, unlike Russula nigricans. The difference between a harmless-looking relative and a deadly one is a colour change that takes minutes to show and is easy to misjudge. It is a reason to get an expert identification, never a test to rely on before eating.

Russula subnigricans is recorded in East Asia. Wikipedia notes that a related species was once misidentified in California, so the group is not only an Asian problem.

• Common ink cap (Coprinopsis atramentaria). Contains coprine, which blocks the body's clearance of acetaldehyde after alcohol. Drinking after eating it brings flushing, nausea, vomiting and a racing heart. Full detail on the common ink cap page.
• Ugly milkcap (Lactarius turpis). A dark olive-brown to olive-black milkcap, 4 to 20 cm across, that grows mainly with birch. Wikipedia reports that it contains necatorin, a highly mutagenic compound, and that boiling lowers the amount but does not remove it. It is still pickled in parts of Eastern Europe and Russia, while Western field guides class it as inedible.
• False morels (Gyromitra). They are reddish-brown rather than black, but they are the look-alike the MDC names for black morels. Their caps are wrinkled and brain-like and their stalks are solid, whereas true morels are hollow. See false morel.

Online lists of "poisonous black mushrooms" often mix three different labels: poisonous (a documented toxin or poisoning cases), inedible (too tough, bitter or small to eat) and unknown. For several black fungi the sources we checked say inedible or disputed, not poisonous:

• Dead man's fingers: MDC says not edible.
• King Alfred's cakes: Wikipedia says inedible. It is a hard, charcoal-like ball.
• Black earth tongues: Wikipedia says they are reported edible but too tough to be of interest.
• Black witches' butter: Wikipedia records conflicting sources. One American field guide calls it inedible but not poisonous; others report it as edible.

Inedible or unknown does not mean harmless. Nobody should eat any of these. But a child who touched a black earth tongue is in a different situation from one who ate part of a blackening brittlegill, and it helps to know which kind of black mushroom you are dealing with before you call for advice.

Two black mushrooms are gathered for food in North America. The MDC field guide lists both as edible species. This site does not give edibility verdicts, and MDC's own pages carry the warnings:

• Black trumpet. MDC notes there are no look-alikes in Missouri, partly because the underside has no gills. That statement covers one state, and Poison Control warns that identification skills learned in one area are not reliable in another.
• Black morel. MDC names false morels and half-free morels as the look-alikes. It says to be absolutely sure of the identification, never to eat morels raw, and to eat only a small amount the first time because of possible reactions.

If you find either one, photograph it, cut one lengthwise to see whether it is hollow, and have the specimen checked by an experienced identifier or a local mycological society. Poison Control's position is that unless you are very experienced in mushroom identification, you cannot tell poisonous species from safe ones.

In recipes and shops, "black mushroom" usually means dried shiitake (Lentinula edodes). Wikipedia lists black mushroom and black forest mushroom among its common names. "Black fungus" means wood ear (Auricularia). Both are cultivated foods rather than wild finds, and each has one well-documented way of making people ill:

• Shiitake dermatitis. DermNet, the New Zealand dermatology reference, describes an itchy rash of red streaks that look like whip marks. It usually appears about 24 hours after eating raw or lightly cooked shiitake, but it can start within a few hours or up to 5 days later. It affects about 2% of people who eat the mushroom raw or lightly cooked and is blamed on lentinan, a compound broken down by heat. DermNet says it clears on its own within a few weeks and that thorough cooking prevents it.
• Soaked black fungus and bongkrekic acid. Hong Kong's Centre for Food Safety (Food Safety Focus, September 2019) linked severe poisonings in mainland China to black fungus. The cause is a soil bacterium that can grow while the fungus soaks and produce bongkrekic acid, which the Centre says is heat-stable and cannot be washed off. Its advice is to keep black fungus in the refrigerator if it needs to soak overnight. A 2023 review in the journal Foods counts more than 3,000 officially documented bongkrekic acid poisonings since 1975, with a case-fatality rate of 40 to 60%, and names rehydrated wood ear among the foods involved.

Anyone who becomes ill after eating either one, especially with vomiting and abdominal pain after soaked black fungus, should call Poison Control or seek medical care straight away.

Treat it as possibly poisonous until it is identified. Most black mushrooms in lawns are inky caps that have started to dissolve, and the common ink cap is one of them. Other black growths in a yard have their own explanations:

• Tiny black "eggs" in little cups in mulch are bird's nest fungi. UF/IFAS Extension says Cyathus species hold dark brown or black egg-like spore packets and stand 1 to 25 mm tall, and that there is no evidence they are toxic to people or animals. That is not a reason to let a child eat them.
• Black specks stuck to light-coloured siding or cars near mulch beds are artillery fungus. University of Delaware Extension describes cup-shaped fruiting bodies about 1/10 inch wide that shoot sticky black spore masses several feet towards light surfaces.
• Large grey-yellow rosettes at the base of an oak that turn black where touched are the black-staining polypore. MDC says it often comes back in the same spot every year.
• Hard black swellings on cherry or plum branches are black knot, a gall caused by the fungus Apiosporina morbosa, not a mushroom. Iowa State University Extension advises pruning at least 2 to 3 inches below each gall while the tree is dormant.

UC IPM advises removing all obvious mushrooms from a yard before small children play there, because children put things in their mouths. More on the lawn species: black mushrooms in yard. If a dog ate one: dog ate mushroom in yard.

You cannot tell by colour, taste, smell or any household test. Poison Control says that unless you are very experienced in mushroom identification you cannot tell poisonous mushrooms from safe ones, that cooking does not make a poisonous mushroom safe, and that symptoms can be delayed for many hours. The California Poison Control System (November 2025) lists these myths:

• "Poisonous mushrooms are brightly coloured." Death caps range from greenish or yellowish to brown or tan.
• "White mushrooms are safe." The destroying angel is pure white.
• "Poisonous mushrooms taste bad." Highly toxic ones can taste pleasant, and a bite or two can be enough.
• "Cooking destroys the poison." Many toxins survive heating and freezing.
• "A silver spoon turns black." Poisonous mushrooms contain nothing that reacts with silver.
• "If animals eat them, they are safe for people." Animals can tolerate mushrooms that are toxic to humans.

The same list also corrects one worry: touching a poisonous mushroom does not poison you; eating it does. Wash your hands anyway, and keep children and pets away from any mushroom you have not identified.

These are the observations that separate the black groups above. Photograph each one, then photograph it with the app so it can identify the mushroom, and keep the notes for whoever gives the final identification.

• Black from the start, or did it turn black? Mushrooms that turn black with age point to inky caps. Mushrooms black from the start point to trumpets, morels or wood-decay fungi.
• Cut a piece and watch it for 20 minutes. Note whether it reddens, blackens, reddens and then blackens, or stays the same. Record the result for the expert. It is not an edibility test.
• Underside: gills, pores, smooth ridges, or nothing (clubs, balls, jelly).
• Hollow or solid when cut lengthwise, which matters for morels and false morels.
• Growing on: lawn, mulch, buried wood, a living tree, a stump or bare burned ground.
• Nearby trees: oak, birch, ash, cherry or plum.
• Spore print colour: inky caps and many small lawn mushrooms print dark. See how to take a spore print.

• Call Poison Control at 1-800-222-1222 (US) now, even if the person feels fine. The service is free and open 24 hours, and its specialists work with mycologists to identify the specimen. Symptoms can be delayed for many hours.
• Mention alcohol if the mushroom might be an ink cap and the person has been drinking, or plans to.
• Keep a specimen in a paper bag, including the base, plus any leftovers from the meal.
• For a dog or cat, call your vet or ASPCA Animal Poison Control at (888) 426-4435. The ASPCA charges a one-time consultation fee.

Research and drafting for this page were assisted by AI and checked line by line against the sources listed below. Nothing on this page says a wild mushroom is safe to eat or safe to handle. If you find an error, tell us and we will correct it.