Licorice
Glycyrrhiza glabra

AVOID

Avoid licorice as it raises blood pressure and interacts with certain blood pressure medications. Some have used rolled licorice sticks as an aide to help them quit smoking cigarettes. In excessive doses (like a bag of candy) it can cause liver toxicity. The sweetness in licorice comes from glycyrrhizin, a compound said to be 50 times sweeter than sugar. Licorice also can prevent high serum potassium for dialysis patients. On the other hand eating large doses of licorice can lead to a very low potassium. It is not related to anise, star anise, or fennel, though it has a similar flavor. Licorice raises blood pressure and lowers potassium by inhibition of the enzyme 11β-hydroxysteroid dehydrogenase, an enzyme that normally inactivates cortisol in the kidney. Cortisol acts at the same kidney receptor as the hormone aldosterone and mimics aldosterone excess. Ace inhibitors and diuretics -- If you are taking angiotensin converting enzyme (ACE) inhibitors or diuretics for high blood pressure, do not use licorice products. Licorice could interfere with the effectiveness of these medications or could worsen possible side effects.