Does Grapefruit Affect Licorice Root?

Amount or timing may matter

The short answer

Glycyrrhizin in licorice is metabolized by CYP3A4. Grapefruit may increase licorice blood levels, worsening hypokalemia and hypertension risk.

How to arrange timing

Separate licorice root from grapefruit by at least 4 hours. Monitor blood pressure.

Reference

Reference noted for this food and supplement combination: Sigurjonsdottir et al., J Hum Hypertens 2001; Examine.com

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.