Commonly called by its Latin first name, Melissa, lemon balm is a native of southern Europe, often planted in gardens to attract bees. Its leaves give off a delicate lemon odor when bruised.

Medical authorities of ancient Greece and Rome mentioned topical lemon balm as a treatment for wounds. The herb was later used orally as a treatment for influenza, insomnia, anxiety, depression, and nervous stomach.

What Is Melissa Used for Today?

Topical lemon balm is most popular today as a treatment for genital or oral herpes. It appears to make flare-ups less intense and last for a shorter period of time, but it doesn't completely eliminate them. Regular use of lemon balm might help prevent flare-ups, but this potential use hasn’t been properly studied.

Note: While conventional treatments can reduce infectivity and thereby help prevent the spread of herpes, there is no evidence as yet that lemon balm offers this benefit. Keep in mind also that common sense methods of avoiding passing on herpes are not entirely effective: Many people are infectious even when they do not have obvious symptoms, and use of a condom does not entirely prevent the spread of the virus. Therefore, if you are sexually active with a noninfected partner who wishes to remain that way, we strongly recommend that you use suppressive drug therapy.

There is some evidence that oral use of lemon balm has sedative effects, and it is currently used for insomnia, anxiety, nervous stomach. There is also some evidence that it may be helpful in colic, and irritable bowel syndrome. Inhaled essential oil of lemon balm may also have calming effects.

What Is the Scientific Evidence for Lemon Balm?

Numerous test tube studies have found that extracts of lemon balm possess antiviral properties.1-3 We don't really know how it works, but the predominant theory is that the herb blocks viruses from attaching to cells.4

One double-blind, placebo-controlled study followed 66 individuals who were just starting to develop a cold sore (oral herpes).5 Treatment with melissa cream produced significant benefits on day 2, reducing intensity of discomfort, number of blisters, and the size of the lesion. (The researchers specifically looked at day 2 because, according to them, that is when symptoms are most pronounced.)

Another double-blind study followed 116 individuals with oral or genital herpes.4 Participants used either melissa cream or placebo cream for up to 10 days. The results showed that use of the herb resulted in a significantly better rate of recovery than those given placebo.

Relatively informal observations suggest that regular use of lemon balm cream may help reduce the frequency of herpes flareups.4

Lemon balm extracts have been found to produce a sedative effect in mice.9 Based on this, human trials have been performed.

In a 4-month, double-blind, placebo-controlled study of 42 people with Alzheimer’s disease, use of an oral lemon balm extract significantly decreased their tendency to become agitated.13

In another study, lemon balm essential oil applied to the skin in the form of a cream also reduced agitation in 71 people with Alzheimer's disease.12 The researchers considered this a form of aromatherapy, a treatment in which the odor of a substance is said to produce the benefit. However, one of the first things to disappear in Alzheimer's disease is the sense of smell; it is more likely, therefore, that the lemon balm worked via absorption through the skin.14

Lemon balm has also shown sedative and anti-anxiety effects in two small studies of healthy people.11,15

Several studies have investigated the effects of combining lemon balm with other herbs. Combination therapies containing lemon balm plus valerian have shown modest promise as treatment of insomnia.7,8 and anxiety.16 Lemon balm plus chamomile and fennel may be effective in reducing crying in babies with colic.17 And, Carmint, an herbal remedy containing lemon balm, spearmint, and coriander, may be beneficial as add-on to standard medication (eg, loperamide or psyllium) in the treatment of irritable bowel syndrome.18

Dosage

For treatment of an active flare-up of herpes, the proper dosage is 4 thick applications daily of a standardized lemon balm (70:1) cream. The dosage may be reduced to twice daily for preventive purposes.

The best lemon balm extracts are standardized by their capacity to inhibit the growth of herpes virus in a petri dish.9 To make sure the extract has been properly prepared, manufacturers place cells in such a growing medium and then add herpes virus. Normally, the virus will gradually destroy all the cells. But when little disks containing lemon balm are added, cells in the immediate vicinity are protected. Although manufacturers use this method as a form of quality control, it also provides evidence that lemon balm really works.

When taken orally for its calming effect, the standard dosage of lemon balm is 1.5 to 4.5 g of dried herb daily; extracts and tinctures should be taken according to label instructions.

Safety Issues

Topical lemon balm is not associated with any significant side effects, although allergic reactions are always possible. Oral lemon balm is on the FDA's GRAS (generally recognized as safe) list. However, according to one study cited above, lemon balm reduces alertness and impairs mental function; for this reason, individuals engaging in activities that require alertness, such as operating a motor vehicle, should avoid using lemon balm beforehand.11

In addition, one animal study suggests that if lemon balm is taken at the same time as standard sedative drugs, excessive sedation might occur.10

Interactions You Should Know About

If you are taking sedative medications, use of oral lemon balm might amplify the effect, potentially leading to excessive sedation.