Licorice has been used a lot for medicinal effect. Herbalists use it to treat the adrenal glands, and Chinese medicine uses it in a variety of treatments. However, it also has another use.
Research has found that when people eat around 25g of licorice, it can affect sex drive. Licorice contains Glycerrhizinic Acid. This acid inhibits the liver's ability to deactivate cortisol incirculation. The result of this is that the cortisol levels rise, and that reduces the action of testosterone. This in turn, reduces sex drive.