Black liquorice or "sweet root" has many uses. Black liquorice is an herb that has many medicinal properties. According to the University of Maryland Medical Center, black liquorice that contains the active ingredient glycyrrhiza can cause serious side effects, especially when combined with other herbs. Individuals who are being treated for any pre-existing medical conditions should not take black liquorice without speaking to a doctor.
According to the University of Maryland Medical Center, the use of black liquorice with the active ingredient glycrrhizin, can cause a serious medical condition known as pseudoaldosteronism. In some people, this has the potential to cause damage to the heart, congestive heart failure and heart attacks. Using black liquorice at high doses is usually the cause of this condition. People who have pre-existing heart disease or a history of heart failure should not take black liquorice.
Taking high doses of black liquorice has the potential to worsen pre-existing conditions or diseases. Those who have kidney disease should not take black liquorice because of the potential for an increase in fluid retention. Increased fluid retention in the arms and legs causes the kidneys to work harder and can cause kidney damage. People who have been diagnosed with hypertension or high blood pressure should not use black liquorice, because of serious adverse effects. Hypertension often causes the organs of the body to work harder. The liver and kidneys can become damaged over time from the effects of hypertension. Taking black liquorice can worsen hypertension.
Black liquorice can interact with certain drugs, causing serious complications. Taking black liquorice with an ACE inhibitor, such as Captopril, can cause decreased effectiveness of the medication. People who are taking diuretics for high blood pressure should not take black liquorice because it can worsen the side effects of the medication. The University of Maryland Medical Center states that there have been reports of women having side effects of low potassium levels and high blood pressure when combining black liquorice and oral contraceptives. Diabetics who take insulin daily should avoid black liquorice due to adverse effects on blood sugar levels.
Allergic reactions can occur with the use of black liquorice. The symptoms associated with allergic reactions are hives, swelling of the face, itching, swelling of the lips, wheezing, swelling of the tongue and difficulty breathing. Serious symptoms such as these can be life-threatening and often require emergency medical care.