The back-garden pharmacy

Lemon balm (Melissa officinalis)

What is it? A hardy, bushy perennial of the mint family, with clusters of small, light yellow flowers.

How does it help? It's a mild sedative, so can help ease tension and anxiety, and also has antibacterial qualities.

How do I use it? After harvesting, tie bundles of five stems and hang in a warm place, such as an airing cupboard. Once dry, strip off the leaves to store in a covered container, and use them as required in an infusion.

Other benefits? As a salve, it may reduce the redness and swelling of cold sores.

What's the evidence? ‘Lemon balm is helpful for soothing the digestive and nervous systems, and clinical trials have shown that it can relieve anxiety,' Dr Walker says. ‘It's been used for sleep problems and its anti-viral properties make it a valuable remedy for the common cold.'

Quick fix? Herbs of Grace Lemon Balm Leaf (£15.80, 100 capsules), from www.nutricentre.com or 020 7436 5122.