Mercury, lead, and other heavy metals in Chinese medicines.

Ninety-nine samples of common Chinese medicines were purchased from Chinese medical shops in Singapore and Malaysia and analyzed for mercury, lead, copper, cadmium, cobalt, iron, and nickel. The majority of these medicines were manufactured in China, Hong Kong, and Malaysia. A few of them were of Singapore and Taiwan origin. Atomic absorption method (both flame and flameless) was used for the analyses. Mercury was found to be present in high concentrations in several of the medicines that were for oral consumption.