Parents have been urged not to give Echinacea to children under 12 years of age by the Medicine and Healthcare products Regulatory Agency (MHRA).
The drugs watchdog said that children have a small risk of experiencing a severe allergic reaction to the drug - which is used to treat colds and flus - which outweigh any potential benefits.
Reactions include rashes, hives, difficulty breathing and, in severe cases, potentially fatal anaphylactic shock.
The warning was just a precautionary measure and the MHRA have said older children and adults could continue to use Echinacea as prescribed.
Richard Woodfield, head of herbal policy at the MHRA, said: "This is not a serious safety issue, but parents and carers need to be aware that children under 12 could have a low risk of developing allergic reactions.
"The measures being taken are precautionary in nature. Parents should not worry if they have given Echinacea to children under 12 in the past."
Story posted by Robert Mair on 20/08/2012