Tradition
The roots and runners of the licorice plant (Glycyrrhiza glabra) have been used for more than 4000 years to flavour or sweeten foods and drinks. In traditional Chinese and Japanese medicine, the plant is used as a treatment for liver disease and stomach ulcers.

Benefits
The active ingredient in licorice is the chemical compound glycyrrhizin. It is antiviral, anti-inflammatory, anti-allergic and antispasmodic, as well as an expectorant and a mild laxative. Licorice root has been used to treat herpes simplex sores, sore throat, coughs, catarrh, bronchitis, colic, mild constipation, gastritis, stomach ulcers, and autoimmune disorders such as rheumatoid arthritis. Licorice also stimulates the adrenal glands, so it can help with problems such as Addison's disease. As licorice is naturally sweet, pharmaceutical manufacturers frequently use it to disguise the bitter taste of children's medicines. It is also mixed into toothpastes, chewing gums and cigarettes. Licorice can boost oestrogen activity and it is used to treat polycystic ovary syndrome (PCOS), a female disorder in which high levels of male sex hormones cause excessive hair growth, acne, obesity and infertility.

Evidence
Shakuyaku-kanzo-to is a Japanese herbal remedy containing equal parts of licorice root and peony. A trial of its effects on PCOS sufferers was published in the International Journal of Fertility and Menopausal Studies in 1994. Study subjects took 7.5g of the remedy daily. The herbal mixture helped to reduce the levels of male sex hormone and to increase ovarian activity. This effect was confirmed in a small 2004 Italian study, published in the journal Steroids, which involved nine women taking 3.5g of a licorice preparation daily over two menstrual cycles. Licorice has also been implicated in the loss of male libido.