Hi Debbie-lee.
It is wise to be cautious for many herbs in the case of serious kidney concerns. Although licorice root is generally considered safe as a food ingredient, if it is consumed over a long period of time or at higher doses, it can cause headaches, fatigue, high blood pressure, and, in the worst case scenario, heart attack (if other signs are ignored). This is due to the effects of licorice on potassium and blood pressure-created by a condition called pseudoaldosteronism. People with hypertension, heart disease or kidney disease are of particular concern and should avoid consuming licorice tea or tinctures at any appreciable dose for more than a day or two. Kidney disease is a concern because of the reduced clearance capacity in the body of the glycyrrhizic acid contained in licorice.
One can source deglycyrrhizinated licorice, but I’m not sure of it’s appropriateness in this case.
With warmth,
Benna