Health food shops usually stock a range of products based on ecinacea extracts that are claimed to be effective against colds and flu-like diseases. The Holland & Barrett website lists 15, for example.
The products typically claim:
HRI Cold & Flu Echinacea is a traditional herbal medicinal product used to relieve the symptoms of colds and influenza (flu) type infections.
They are popular products and many people clearly believe they work.
So is there any reliable evidence that they do?