Is Chaga mushroom harmful to the kidneys?

Yes, Chaga mushrooms aren't good for kidneys. With high oxalates content, Chaga mushrooms can increase the risk of kidney stones as well as other kidney diseases. If you are taking Chaga mushroom for a specific reason, you should be cautious about the dosage to avoid having high oxalates in the body, People with existing or prior kidney issues should avoid Chaga mushrooms.