Wood Ear

Safety first: spoiled soaked wood ear. A 2024 case report describes a 77-year-old woman who died after eating Auricularia auricula that had been soaked in water for about five days; the toxin involved, bongkrekic acid, comes from a bacterium and is described as extremely heat-resistant. [1] The report says food contaminated with it looks, smells and tastes the same as safe food. [1] The report does not give a safe soaking time, so follow the package or recipe you have, and do not keep soaked mushrooms for days. If someone becomes ill after eating spoiled food, call Poison Help at 1-800-222-1222 (US), or 911 for collapse or confusion. See Poisoning: What to Do First.

What wood ear is

Wood ear, also called black fungus or cloud ear, is a gelatinous (jelly-like) fungus in the genus Auricularia, family Auriculariaceae. This page is about it as a food. It is not a guide to supplements. Two accepted species names that appear in the research are Auricularia auricula-judae (Bull.) Quél. and Auricularia heimuer F.Wu, B.K.Cui & Y.C.Dai. [2] [3] A review of A. heimuer says it is a different species from A. auricula-judae, which was used in earlier characterization work, and that it has been cultivated in China for more than 1000 years. [4] A review of polysaccharides lists A. auricula-judae, A. auricula, A. polytricha and A. cornea var. Li as common species. [5]

Which species is in a given package is not always clear from a label, and we did not verify here which of those names are synonyms. Research results belong to the species and preparation a study used, and may not carry over to another.

Traditional use and food use

A review describes the use of A. auricula-judae for health purposes as a long tradition in Asia, and notes that research on it has focused narrowly on polysaccharides. [6] That is a description of tradition. It is not proof that the food does anything for a condition. The fruiting body is the part eaten.

What research shows

The constipation trial found that the version with additives was more effective but may cause abdominal discomfort or pain. [7] Do not read this as a claim that eating wood ear treats constipation.

Related pages

Cooking Edible Mushrooms Safely, Storing Mushrooms and Food Safety and Fresh vs Dried Mushrooms.

Lab data and chemistry

This section lists what laboratory papers and food tables report. It describes the mushroom, not a treatment. Wood ear goes by many names (wood ear, cloud ear, black fungus, heimuer) and the Latin names differ by country and by author. One recent review says heimuer has been reclassified as A. cornea, while GBIF lists A. heimuer as its own name, so results below are tied to the exact species a paper names. [3] [12]

A. What the laboratory literature reports in this mushroom

The open chemistry database route (Wikidata and the LOTUS initiative, retrieved 2026-10-23) lists 0 compounds for A. auricula-judae, A. heimuer and A. cornea, so the table below comes only from papers we read. "Reported" means found in at least one study of the species, not present in every product.

B. Measured values

The USDA entry is a food-table record for dried "cloud ears"; it does not name the species. All its values are per 100 g of dried product, so a soaked, cooked portion holds far more water and far smaller numbers. The 50-strain study reports highest and lowest strains, not typical products. Its abstract gives a top iron value of 788 mg per kg for strain Ac3, but its Table 3 shows 788 for manganese in that strain, so we left iron out. [11]

C. What the numbers do and do not mean

• Values vary with species, strain, substrate, harvest and drying. In the 50-strain study copper differed about 60-fold between strains. [11]


• A food-table or lab value is not evidence of a health effect. High fibre and iron on a dried-weight table do not show that eating wood ear improves any condition. [10]


• Dried and soaked mushroom are different foods per gram. Compare food and supplement amounts with care; see Fresh vs Dried Mushrooms.


• "Polysaccharide" figures depend on the test. A colour test for total sugars (used in [11]) is not the same as an enzyme test for beta-glucan, so numbers from different papers do not line up.


• Most supplements discussed in research are extracts or fibre powders, not the soaked mushroom. A small 2025 randomized trial of an A. auricula-judae powder food (24 intervention and 26 control adults, 8 weeks) found no significant change in gut measures or constipation, but reported lower waist size and triglycerides in the intervention group; the authors list the small sample as a limit. [14]