The back-garden pharmacy

Echinacea (Echinacea angustifolia)

What is it? An herbaceous plant, with dark green leaves, sturdy branching stems, and daisy-like flowers.

How does it help? It's a fantastic immune booster and studies have shown it can even help lessen the duration and symptoms of a cold.

How do I use it? Take the leaves or root from a two to three-year-old plant while it's in bloom. There are two ways to make tea - infusion or decoction (using the root). For the infusion, place 5-10g of dried echinacea or 10-20g of the fresh herb in teapot, add boiling water, and steep for 15-20 minutes. For a decoction, place 10g of dried root and 250ml of water in a pot, cover, boil, then simmer for 20-60 minutes. Strain before drinking.

Other benefits? Can help insect bites, eczema and psoriasis.

What's the evidence? ‘Echinacea's traditional use by North American native people was to counter infections,' Dr Walker says. ‘Modern research is showing that constituents in the herb have multiple effects which make the immune system more effective.'

Quick fix? Try Pharmacy2U's echinacea standardised extract (£9.75, 90 tablets); from www.netdoctor-pharmacy.co.uk.