People have been warned not to use a number of unlicensed traditional Chinese medicines (TCMs) by the UK's medicines safety agency.

The Medicines and Healthcare Products Regulatory Agency (MHRA) is warning people not to use a number of these medicines, which are commonly available on the internet, after they were found to contain dangerously high levels of lead, mercury and arsenic.

One product, Bak Foong Pills, which is used for the treatment of menstrual pain, has been recalled in Hong Kong after it was found to contain up to twice the level of lead permitted by the Hong Kong Government.

Another TCM, Hairegenerator, used for the treatment of hair loss, has also been recalled in Hong Kong after a sample was found to contain 11 times the permitted level of mercury.

The Swedish National Food Agency (SFNA) has also found extremely high levels of arsenic in products going by a variety of names. These include Niu-Huang Chieh-tu-pein, Divya Kaishore Guggul and Chandraprabha Vati.

These are used for the treatment of mumps, sore throat, tonsillitis, toothache, skin infections, anorexia and fever in young children.

The UK's MHRA says all of these products are unlicensed and are not authorised for sale in the UK. 

They have, however, been found to be available on the internet and people are warned to be vdry cutious when buying unlicensed medicines, as they have not been assessed for safety and quality and standards can vary widely.

The MHRA said the adulteration of traditional Chinese medicines with heavy metals is a significant international problem and can pose a serious risk to public health.