There has been a valid concern of the toxicity of certain Ayurvedic and unani formulations as they contain heavy metals. In the same way as there are valid concerns about the toxicity of certain allopathic medicines, vaccines, etc.
Keeping all this evidence and talk in mind, my family and I have been taking ayurvedic medication prepared by a person whom we trust. REcently, I came across this article and research paper on testing the ayurvedic PROCESSES. They too, done verify the quality of the products available in the market.
You can check it out.
http://journals.iucr.org/s/ ( the original paper)
http://www.thehindu.com/sci-tech/why-rasasindura-is-not-toxic/article7619239.ece (article in The Hindu- an Indian newspaper)