DNA testing of traditional Chinese medicines has shown that many contain traces of endangered animals.
Scientists who analysed 15 samples of powders, pills, capsules and herbal teas found "multiple" examples of banned animal ingredients.
Some of the samples also contained potentially toxic plant compounds and allergy triggers.
The traditional Chinese medicines (TCMs) studied were among products seized by Australian border officials.
Dr Michael Bunce, from Murdoch University in Western Australia, said: "In total we found 68 different plant families in the medicines - they are complex mixtures of species.
"Some of the TCMs contained plants of the genus Ephedra and Asarum. These plants contain chemicals that can be toxic if the wrong dosage is taken, but none of them actually listed concentrations on the packaging.
"We also found traces from trade-restricted animals that are classified as vulnerable, endangered or critically endangered, including the Asiatic black bear and Saiga antelope."
Until now it has been difficult to determine the biological origins of TCMs processed into pills and powders.
The new research, published in the online journal Public Library of Science Genetics, used high-throughput DNA sequencing to unravel the complex mixtures of plant and animal ingredients.
Murdoch University Phd student Megan Coghlan, who took part in the research, said: "We found multiple samples that contained DNA from animals listed as trade-restricted according to the Convention on International Trade in Endangered Species Legislation. Put simply, these TCMs are not legal."
Another concern was the mislabelling of TCMs, leading to confusion for consumers and making it more difficult to prosecute illegal traders.
"A product labelled as 100% Saiga antelope contained considerable quantities of goat and sheep DNA," said Dr Bunce. "Another product, Mongnan Tianbao pills, contained deer and cow DNA, the latter of which may violate some religious or cultural strictures."
He added: "It is hoped that this new approach to genetically audit medicinal products will bring about a new level of regulation to the area of complementary and alternative medicine. Auditing TCMs would assist in prosecuting individuals who seek to profit from the illegal trade in animal products."