Two herbal remedies used for centuries to alleviate anxiety have won the backing of scientists.
Researchers found "strong evidence" that passion flower- extract and kava both combat anxiety disorders.
Pooled results from an analysis of 24 studies, involving more than 2,000 participants, also indicated that St John's Wort, which is commonly taken to relieve depression, and magnesium supplements were not effective.
Study leader Shaheen Lakhan said: "Our review and summary of the literature on herbal remedies and dietary supplements for anxiety should aid mental health practitioners in advising their patients and provide insight for future research in this field."
Passion flower is widely recommended as a treatment for restlessness and nervousness. However, it is unclear which of the thousands of chemicals in the plant are responsible for its effects.
Kava is a drink prepared from the plant piper methysticum. It has been consumed in many cultures for centuries and is said to relieve anxiety, restlessness and insomnia.