It grows to 70-150 cm tall. The leaves have a gentle lemon scent, related to mint. At the end of the summer, little white flowers full of nectar appear. These attract bees, hence the genus name Melissa (Greek for 'honey bee'). Its flavour comes from the terpenes citronellal, citronellol, citral, and geraniol.
Lemon Balm grows in clumps and spreads vegetatively as well as by seed. In mild temperate zones, the stems of the plant die off at the start of the winter, but shoot up again in spring. It can be easily grown from stem cuttings rooted in water, or from seeds. Under ideal conditions, it will seed itself prolifically and can become a nuisance in gardens.
Lemon balm is often used as a flavouring in ice cream and herbal teas, both hot and iced, often in combination with other herbs such as spearmint. It is also frequently paired with fruit dishes or candies.
The crushed leaves, when rubbed on the skin, are used as a repellant for mosquitos.
Lemon Balm is also used medicinally as a herbal tea, or in extract form. It is claimed to have antibacterial, antiviral properties (it is effective against herpes simplex), and it is also used as a mild sedative or calming agent. At least one study has found it to be effective at reducing stress, although the study's authors call for further research. Its antibacterial properties have also been demonstrated scientifically, although they are markedly weaker than those from a number of other plants studied.
Lemon balm should be avoided by those on thyroid medication (such as thyroxine) as it is believed that the herb inhibits the absorption of this medicine.
Despite extensive traditional medicinal use, melissa oil has been prohibited by the International Fragrance Association (IFRA)'s 42nd amendment.