Wood ear mushroom (Auricularia species, also sold as black fungus or cloud ear) is a low-fat, high-fiber fungus that is unusually rich in iron for a plant-based food. Laboratory and animal studies have found compounds in wood ear that act on blood clotting, which lines up with centuries of traditional use around circulation. No human clinical trials have tested wood ear for a cardiovascular outcome, so its blood-thinning reputation is still preclinical, not proven.
If you take warfarin, a direct oral anticoagulant, aspirin, clopidogrel, or another blood-thinning medication, talk with your prescribing clinician before adding concentrated wood ear products to your routine. Watch for unusual bruising, nosebleeds, bleeding gums, blood in urine or stool, or bleeding that will not stop, and get medical care right away if any of these happen.
Nutritional Profile: Iron, Fiber and Calories
The values below come from the USDA FoodData Central entry for dried cloud ear fungus. These figures describe the dried product as sold, not a rehydrated serving, which is important because dried wood ear is usually soaked before cooking and a real serving weighs far less than 100 grams once it absorbs water.
- Calories: ~284 kcal
- Protein: ~9 g
- Fat: Under 1 g
- Carbohydrate: ~73 g
- Dietary fiber: ~70 g
- Iron: ~6 mg
- Potassium: ~754 mg
- Calcium: ~159 mg
Two things stand out. First, the fiber content is exceptionally high, though this is measured on dried weight and a typical cooked serving delivers a smaller fraction of it. Second, the iron content is notable for a fungus, but iron from plant and fungal sources (non-heme iron) absorbs less efficiently than iron from meat, so it should not be treated as a substitute for a clinician-guided approach to diagnosed iron deficiency.
Traditional Use: Circulation and “Blood-Moving” Foods
In traditional Chinese food and medicine practices, wood ear has long been categorized among foods believed to support circulation and move blood. This traditional classification is a historical and cultural data point, not a clinical finding. It helps explain why researchers became interested in testing wood ear’s effect on clotting, but tradition alone does not establish that a food is safe or effective for a medical purpose.
Cardiovascular and Anticoagulant Research: What Has Actually Been Studied
Researchers have isolated polysaccharide compounds from Auricularia auricula and tested them outside the body and in animals. A laboratory study published in the journal Thrombosis Research identified a polysaccharide from Auricularia auricula with anticoagulant activity, and reported that the effect appeared to work through antithrombin, a natural clotting-control protein. Separately, a study in mice found that a polysaccharide isolated from Auricularia auricula reduced markers of induced thrombosis in the animals.
These are legitimate, peer-reviewed findings, and they are the reason wood ear has a reputation as a “blood-thinning” mushroom. But both studies tested an isolated compound extracted in a lab, not the whole mushroom as eaten, and neither was conducted in humans. A compound behaving one way in a test tube or a mouse does not guarantee the same effect at the same strength when a person eats wood ear as food or takes a supplement.
Where this evidence sits on the hierarchy
Using the same evidence-grading approach applied across this site (see our evidence grading and source policy), the cardiovascular and anticoagulant research on wood ear currently sits at Grade D: cell-based and animal research without a direct human clinical trial behind it. No randomized controlled trial has tested wood ear mushroom, in food form or as a supplement, for a cardiovascular outcome in people. That gap is the single most important fact for anyone weighing a “heart health” claim about this mushroom.
- Human clinical trials: None identified — cannot confirm an effect in people
- Animal studies: Mouse thrombosis model — suggests a mechanism worth studying further
- In-vitro / mechanistic: Isolated polysaccharide acting through the antithrombin pathway — explains a possible mode of action
- Traditional use: Long history as a circulation-supporting food — historical context, not clinical proof
Safety Considerations and Extra-Caution Groups
Wood ear mushroom is widely eaten as food, particularly in soups and stir-fries, and food-level use has a long history of general dietary use. Concentrated extracts or supplements are a different exposure than a food serving, and research on concentrated products is limited. The following groups warrant extra caution and a conversation with a qualified clinician before using wood ear supplements or eating large amounts regularly:
- Anyone taking warfarin, a direct oral anticoagulant, aspirin, clopidogrel, or another antiplatelet or anticoagulant medication
- Anyone with a diagnosed bleeding disorder or history of unusual bleeding
- Anyone scheduled for surgery or a dental procedure, since supplements are often advised to be paused beforehand
- Pregnant or breastfeeding individuals, since supplement-level safety data is limited
- Anyone managing iron overload conditions, given wood ear’s iron content
Checklist: Before You Add Wood Ear to Your Routine
- Confirm whether you are using wood ear as a food ingredient or as a concentrated supplement — the evidence and the risk profile differ
- List any blood-thinning or antiplatelet medications you currently take
- Ask your prescribing clinician whether wood ear is appropriate alongside your specific medication and health history
- If you notice unusual bruising, bleeding, or blood in urine or stool, stop use and seek medical attention
- Treat any cardiovascular claim about wood ear as preclinical until human trial data exists
Frequently Asked Questions
Does wood ear mushroom actually thin the blood in humans?
Isolated compounds from wood ear have shown anticoagulant activity in lab and animal research, but no human clinical trial has confirmed this effect in people eating the mushroom or taking a supplement. The honest answer is that it may have this effect, but it has not been proven in humans.
Is wood ear mushroom high in iron?
Yes, relative to most plant and fungal foods, dried wood ear contains a meaningful amount of iron per 100 grams according to USDA FoodData Central. It is non-heme iron, which the body absorbs less efficiently than iron from animal sources.
Can I eat wood ear mushroom if I take a blood thinner?
This is a decision for your prescribing clinician, who knows your medication, dose, and health history. Because animal and lab research suggests wood ear may affect clotting, it is a reasonable and important question to raise before regular or concentrated use.
Is wood ear mushroom the same as black fungus?
Yes, “black fungus,” “cloud ear,” and “wood ear” are common names used for Auricularia species. For a broader overview of this mushroom’s research and safety profile, see our full wood ear (black fungus) species profile.
Educational Disclaimer
This article is for educational purposes only and is not medical advice. It does not diagnose any condition, prescribe any treatment, or guarantee any outcome. Do not start, stop, or change any medication, including blood-thinning medication, based on this article. Talk with a qualified healthcare provider about your specific health history and medications before using wood ear mushroom as a supplement. For general guidance on evaluating mushroom safety and medication interactions, see our mushroom safety and interactions guide, and browse other species in our mushroom health benefits encyclopedia.