Licorice is likely safe for most people when taken by mouth in amounts found in foods. Licorice is possibly safe when taken by mouth in larger amounts for medicinal purposes and when applied to the skin for a short amount of time. However, it is possibly unsafe when taken by mouth in large amounts for more than 4 weeks or in smaller amounts long-term. Consuming licorice daily for several weeks or longer can cause severe side effects including high blood pressure, low potassium levels, weakness, paralysis, and occasionally brain damage in otherwise healthy people. In people who eat a lot of salt or have heart disease, kidney disease or high blood pressure, as little as 5 grams per day can cause these problems.
Other side effects of licorice use include tiredness, absence of a menstrual period in women, headache, water and sodium retention and decreased sexual interest and function in men.
People who chew tobacco flavored with licorice might develop high blood pressure and other serious side effects.
Special Precautions & Warnings:
Pregnancy and breast-feeding: It is unsafe to take licorice by mouth if you are pregnant. High consumption of licorice during pregnancy, about 250 grams of licorice per week, seems to increase the risk of early delivery. It might cause a miscarriage or early delivery. There is not enough reliable information about the safety of taking licorice if you breast feeding. Stay on the safe side and avoid use.
Heart disease: Licorice can cause the body to store water and this can make congestive heart failure worse. Licorice can also increase the risk of irregular heartbeat. Do not consume licorice if you have heart disease.
Hormone-sensitive conditions such as breast cancer, uterine cancer, ovarian cancer, endometriosis or uterine fibroids: Licorice might act like estrogen in the body. If you have any condition that might be made worse by exposure to estrogen, do not use licorice.
High blood pressure: Licorice can raise blood pressure. Do not consume large amounts of it if you have high blood pressure.
A muscle condition caused by nerve problems (hypertonia): Licorice can cause the level of potassium to drop in the blood. This can make hypertonia worse. Avoid licorice if you have hypertonia.
Low potassium levels in the blood (hypokalemia): Licorice can lower potassium in the blood. If your potassium is already low, licorice might make it too low. Do not use licorice if you have this condition.
Kidney disease: Overuse of licorice could make kidney disease worse. Do not use it.
Sexual problems in men: Licorice can lower a man’s interest in sex and also worsen erectile dysfunction (ED) by lowering levels of a hormone called testosterone.
Surgery: Licorice might interfere with blood pressure control during and after surgery. Stop taking licorice at least 2 weeks prior to a scheduled surgery.