Licorice is typically used in many herbal formulas as a support herb to help carry the herbs to the body. It is used in small doses.
When licorice over long periods of time in large doses, yes, there are some drawbacks depending upon which type of licorice that you use. It may help if you read the 2 links below.
Licorice -- Take 2 to 3 grams (2,000 to 3,000 milligrams) of licorice root (not deglycyrrhizinated licorice [DGL]) twice a day for six to eight weeks. The patient may then taper off over a period of ten to fourteen days. Licorice can raise blood pressure or cause an overly high cortisol level if taken on an ongoing basis. It is best used short-term as a "jump-start" in raising cortisol levels. It also has antiviral properties, which can be very helpful in CFS.
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In this link there are some studies on the herb.