Valerian, native to Europe and North America, has long been used to treat anxiety, stress, muscle tension and insomnia. It contains valerenic acid and valeranon that help the body relax into a calm state so that sleep can come naturally.

What you need to know before taking valerian:

• It should not be taken with any other sleep-enhancing drugs.

• It should not be taken during pregnancy or breast-feeding.

• It can cause drowsiness so should not be taken before driving or during any activity which requires you to be alert.

• It is not suitable for children.

• It can be combined with other herbs such as lemon balm, hops and passionflower.