Are there any possible problems or complications?
This product is sold as a dietary supplement in the United States. Unlike drugs (which must be tested before being allowed to be sold), the companies that make supplements are not required to prove to the Food and Drug Administration that their supplements are safe or effective, as long as they don't claim the supplements can prevent, treat, or cure any specific disease.
Some such products may not contain the amount of the herb or substance that is written on the label, and some may include other substances (contaminants). Actual amounts per dose may vary between brands or even between different batches of the same brand.
Most such supplements have not been tested to find out if they interact with medicines, foods, or other herbs and supplements. Even though some reports of interactions and harmful effects may be published, full studies of interactions and effects are not often available. Because of these limitations, any information on ill effects and interactions below should be considered incomplete.
The maitake mushroom itself has been used as food for centuries and is generally presumed to be safe. So far, studies have not shown any adverse effects from maitake D-fraction or beta glucan, but human studies of their effectiveness in treating cancer have not yet been completed.
In animal studies, beta glucans of the type in maitake mushrooms lowered blood sugar and should be used with caution in people with low blood sugar (hypoglycemia) or those who are on medicines to reduce or control blood sugar. Beta glucans also reduced blood pressure in animals and may have a similar effect in people. Additional studies are needed to find out whether these effects occur in humans.
Allergies to many types of mushrooms, including maitake, have been reported. Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.