The pills were banned in July 1999
A Chinese medicine which can cause cancer is on sale in the UK despite warnings to take it off the market.
The Medicines and Healthcare products Regulatory Agency says more than 900 packs of poisonous Jingzhi Kesou Tan Chuan Wan are circulating in shops.
The news comes weeks after a criminal court heard how a UK woman developed kidney failure and cancer after taking pills containing toxic Aristolochia.
Anyone who may have taken the medicine should call their doctor, experts say.
The unlicensed herbal product was distributed to 20 traditional Chinese medicine and herbal medicine outlets throughout the UK.
The distributor, Ekong International (UK) Ltd, issued a recall last month, but more than three quarters of the stock has still not been returned.
Packs of the product, brought to the UK from China, have had a new English label put on to hide the original label which contained the Chinese symbols for Aristolochia, a banned toxic and carcinogenic derivative of a plant.
The medicine is packed in white plastic bottles, each containing 180 round white tablets.
Richard Woodfield, head of herbal policy at the MHRA, said: "This is a clear example where natural does not necessarily mean safe.
"Aristolochia is a highly toxic plant that can cause serious injury and even death if taken.
"I would strongly advise anyone who has used this product to stop taking it and to immediately consult their doctor."