Glycyrrhizin—a compound found in licorice root—has been tested in a few clinical trials in hepatitis C patients, but there’s currently not enough evidence to determine if it’s helpful. Laboratory studies done in Japan (where an injectable glycyrrhizin compound is used in people with chronic hepatitis C who do not respond to conventional treatment) suggest that glycyrrhizin may have some effect against hepatitis C.

There’s some evidence that topical licorice extract may improve skin rash symptoms, such as redness, swelling, and itching.

A Finnish study of mothers and their young children suggested that eating a lot of actual licorice root during pregnancy may harm a child’s developing brain, leading to reasoning and behavioral issues, such as attention problems, rule-breaking, and aggression.

Studies of licorice root extracts in people for cavities, mouth ulcers, and oral yeast infections have returned mixed results.