Both melissa leaf extracts and its essential oil have spasmolytic activity. The aqueous extract is also effective against different types of viruses, especially herpes simplex virus.
These same compounds are also primarily responsible for the anti-inflammatory and antioxidant activity of melissa preparations.
The essential oil has antibacterial and antifungal activity.
The European Medicine Agency (EMA) recommends the traditional use of its infusion and extracts to relieve the symptoms of stress and to facilitate sleep, as well as for mild digestive disorders such as bloating and flatulence.
The ESCOP further recommends the use of aqueous extract to topically treat cold sores, being more effective the sooner treatment starts.