Does Grapefruit Affect Black Cohosh?

Amount or timing may matter

The short answer

Black cohosh is partially metabolized by CYP3A4. Grapefruit may increase its blood levels, raising the risk of hepatotoxicity.

How to arrange timing

Separate black cohosh from grapefruit by at least 4 hours. Monitor for signs of liver stress.

Reference

Reference noted for this food and supplement combination: Examine.com; Gurley et al., Mol Nutr Food Res 2008

Important context

The effect can also change with food amount, supplement dose, product formulation, health conditions, and medication use. Ask a doctor or pharmacist first if you take medication, are pregnant or breastfeeding, or have a chronic condition.