Letter: Hidden danger of herbal pills

CALLUM MURRAY is quite right to query the value of 'natural' herbal 'tranquillisers' such as valerian ('How to keep calm the natural way - or not', 6 June). Of far greater concern are reports in the British Medical Journal that this particular herb may cause severe liver damage. Despite this most pharmacists and health supplement retailers seem unaware of any possible adverse effect, and the manufacturers of valerian products are not required to give any warning to the general public.

Charles Shepherd

Chalford Hill, Glos