Ganoderma lucidum or reishi mushroom: Benefits and toxicity


Ganoderma lucidum, commonly known as reishi mushroom, has been studied for its potential health benefits, although the evidence varies in strength and quality. Research indicates possible therapeutic properties in several areas:

  1. Immune System Support: Some studies suggest that Ganoderma lucidum can enhance immune function through its effects on white blood cells, which can be beneficial for fighting infections and cancer. However, these studies are often preliminary.
  2. Anti-Cancer Properties: There is some evidence to suggest that it may help fight cancer cells or alleviate chemotherapy side effects. Nevertheless, more robust clinical trials are needed to establish effective use and safety in cancer treatment.
  3. Cardiovascular Health: It has been proposed that Ganoderma lucidum could help lower blood pressure and cholesterol levels, contributing to heart health. However, the evidence is not conclusive, and further studies are required.
  4. Antioxidant and Anti-inflammatory Effects: The mushroom is rich in antioxidants, which might help reduce inflammation and prevent cellular damage.
  5. Liver Health: Some studies have investigated the hepatoprotective properties of Ganoderma lucidum, suggesting it may help improve liver function in individuals with hepatitis and other liver conditions. However, these findings need further validation through large-scale clinical trials.
  6. Anti-diabetic Effects: Preliminary research indicates that Ganoderma lucidum might help lower blood glucose levels, making it a potential supplement for managing diabetes. However, the interaction with conventional diabetes medications and the overall impact on diabetes management require careful study and professional guidance.
  7. Neuroprotective Properties: There is emerging evidence that suggests Ganoderma lucidum may have neuroprotective effects, potentially beneficial in conditions like Alzheimer’s and Parkinson’s diseases. The mechanisms likely involve its anti-inflammatory and antioxidant effects, but definitive evidence from human studies is still lacking.
  8. Sleep and Mental Health: Anecdotal evidence and some small-scale studies suggest that Ganoderma lucidum may help improve sleep quality and reduce anxiety and depression. However, more rigorous research is needed to confirm these effects.
  9. Allergies and Respiratory Health: Some research suggests that Ganoderma lucidum may help reduce allergic reactions by inhibiting histamine release. Its potential benefits for respiratory health, particularly in chronic respiratory conditions like asthma, also warrant further investigation.

Despite these potential health benefits, the clinical evidence supporting Ganoderma lucidum as a treatment for specific conditions remains inconclusive, and more high-quality research is needed to determine its efficacy and safety. The quality of the supplement, dosage, and individual health status can significantly influence its safety and effectiveness. Additionally, potential interactions with other medications must be carefully considered.

Ganoderma lucidum can have potential side effects and toxicities, especially if taken in high doses or for an extended period. Here are some key considerations regarding the toxicity and safety of Ganoderma lucidum:

  1. Liver Toxicity: Although reishi is often touted for its liver-protective effects, there have been rare reports of liver toxicity associated with its use. These cases typically involve prolonged use of high doses. It is crucial for individuals with pre-existing liver conditions or those taking other hepatotoxic drugs to use reishi under medical supervision.
  2. Allergic Reactions: Some people may experience allergic reactions to Ganoderma lucidum, especially those who are allergic to other mushrooms. Symptoms can include skin rashes, itching, or difficulty breathing.
  3. Gastrointestinal Discomfort: Common side effects include digestive issues such as nausea, upset stomach, and diarrhea. These are generally mild and may decrease with continued use or adjustment of the dosage.
  4. Blood Thinning: Ganoderma lucidum may possess anticoagulant properties, which can increase the risk of bleeding, particularly in people taking blood thinners such as warfarin or those with bleeding disorders.
  5. Interaction with Other Medications: Reishi can interact with certain medications, including those for blood pressure, immune suppression, and cancer treatment. It is essential to consult with a healthcare provider to avoid adverse interactions.

Given these potential risks, it is advisable for anyone considering the use of Ganoderma lucidum to do so under the guidance of a healthcare professional, particularly if they have underlying health conditions or are taking other medications.

Dr. Christos Zavos, as a gastroenterologist and hepatologist, is well-equipped to advise patients on the safe use of supplements like Ganoderma lucidum. Patients can reach out to Dr. Zavos via the contact form on his website,, or directly contact him through his office in Thessaloniki, Greece, for personalized advice and to ensure that any supplement use is safe and effective in relation to their specific health conditions.

Last update: 30 April 2024, 21:12


Gastroenterologist - Hepatologist, Thessaloniki

PhD at Medical School, Aristotle University of Thessaloniki, Greece

PGDip at Universitair Medisch Centrum Utrecht, The Netherlands

Ex President, Hellenic H. pylori & Microbiota Study Group