Chinese herbal medicines have a history dating back 4000 to 5000 years ago. Ayurvedic (Indian) and Chinese herbal medicines are, perhaps, the oldest systems of plant based medicines on the planet. Chinese herbal medicines are mainly plant based, but may contain other substances as well. Plant based substances may include the roots, bark, seeds, flowers and leaves carefully chosen for their curative powers. There is some concern that Chinese herbal medicines imported from China could be contaminated with toxic substances like heavy metals, dyes, and chemicals used in the extraction and manufacturing processes. There are many reputable American companies that make high quality Chinese formulations with American processing certifications.