But Los Angeles-based researchers now say there's 'strong evidence' that extracts of the herbs passion flower and kava help relieve anxiety. The scientists, from the Global Neuroscience Initiative Foundation, backed both plants for their soothing, relaxing abilities.
Passion flower (or passiflora) is an age-old folk remedy for stress and anxiety that has been used around the world. It's available as tablets as well as a liquid extract or tincture (available at most health stores).
Kava, which comes from the plant Piper methysticum, is traditionally prepared as a drink. But you won't be able to get your hands on it in the UK, as it was banned several years ago because of fears of side effects.
The scientists, writing in Nutrition Journal, claim two amino acids - L-lysine and L-arginine - may also help people deal with stress and worry. Both nutrients are available from health stores.
However there was bad news for St John's Wort, a popular herbal remedy for mild depression. The US researchers claimed they didn't find evidence that it worked. The same, they say, applies to magnesium supplements.
Do you regularly use herbal or other natural remedies and find them helpful? If so, what do you say to the scientists who insist they are merely a placebo?