Is reishi mushroom safe during pregnancy?

What does the evidence say about reishi mushroom during pregnancy?

1. Ganoderma lucidum, known as reishi in Japan and lingzhi in China, has a long history of traditional use and contains bioactive compounds that have been studied mainly in non-pregnant adults and animal models. 1
2. In clinical trials, reishi has generally been well tolerated, with therapy showing no meaningful change in blood counts or liver enzyme levels, though rare individual case reports of liver injury have been described. 2
3. Herbal supplements broadly haven't all been evaluated for pregnancy or breastfeeding use, and some have been found to contain contaminants like heavy metals or ingredients not listed on the label, part of why checking with a provider before starting any herbal product matters. 3
4. Many dietary supplements haven't been tested in pregnant women, and some can increase bleeding risk or affect how anesthesia works, so full disclosure of any supplement use to your healthcare providers, especially before a procedure, is standard guidance. 4
5. The only formal toxicity data located for reishi is a short animal study, in which rats given the extract for three months as part of colon-cancer research showed no signs of toxicity, underscoring how little is actually known beyond short-term, non-pregnancy research. 1

Is reishi mushroom safe in each trimester?

• First trimester. There's no dedicated first-trimester data on reishi, and this is generally the most sensitive window for any unstudied supplement, so it's a reasonable one to skip until you've talked with your provider.
• Second trimester. The safety picture doesn't change much by trimester since the research gap is really about pregnancy as a whole, not a specific window, so the same caution from the first trimester still applies here.
• Third trimester. If reishi is being considered for immune support heading into cold and flu season, general dietary-supplement guidance about disclosing herbal use becomes especially relevant now, since some supplements can affect bleeding or interact with anesthesia if a procedure or delivery intervention comes up.