If your blood pressure is too low, it is best to avoid reishi mushroom. Stop using reishi mushroom at least 2 weeks before a scheduled surgery.

Reference: https://lifeforceresearch.center/chemical-biochemical-preclinical-and-clinical-studies-of-ganoderma-lucidum-polysaccharide-as-an-approved-drug-for-treating-myopathy-and-other-diseases-in-china/