One study illustrated this effect on the central nervous system when administered to laboratory mice. Lemon balm has also found an application in treating certain psychiatric conditions, particularly those in which nervousness and headache are experienced. Since the 10th century, lemon balm has been used as a tranquilizer and sleep aide. Charlemagne, or Charles the Great, appreciated the calming effect of this herb so much that he proclaimed it be grown in every medicinal herb garden within his domain. The long-held belief that placing the fresh leaves upon a wound, or using the tea to combat colds and fevers is supported by the plant's antiviral and antihistamine action.
Some studies suggest the tea prevents the cell division of certain tumors.
The leaves of lemon balm are often added to potpourri and sachets to freshen fine clothing and linen. Shakespeare's The Merry Wives of Windsor recommend rubbing the leaves on wood to produce a glossy shine and lemony scent. In spite of the fact that the plant is particularly irresistible to honeybees, it is often burned or its leaves applied to the skin to repel insects. In fact, the leaves contain the essential oils citral and citronella oil, giving credence to this claim. The fresh leaves and flowers of lemon balm complement all vegetable and fruit salads, stuffings, bean dishes, and marinades for meat and fish.