Safety concerns

There is evidence that using some ayurvedic medicine, especially those involving herbs, metals, minerals, or other materials involves potentially serious risks, including toxicity.

A research study published in 2004 in the Journal of the American Medical Association studied the chemistry of ayurvedic compounds and found significant levels of toxic heavy metals such as lead, mercury and arsenic in 20% of Ayurvedic preparations that were made in South Asia for sale around Boston and extrapolated the data to America. The Journal found that, if taken according to the manufacturers' instructions, this 20% of remedies "could result in heavy metal intakes above published regulatory standards" Similar studies have been performed in India, and have confirmed the presence of heavy metals. The main concern of metal toxicity from misuse of ayurvedic medicines are well known. What is not well-known however is the field and detailed knowledge of Rasa Shastra, the practice of using heavy metals therapeutically as anti-microbials and anti-cancer agents much as cisplatin or silver are used in mainstram medicine. In Rasa Shastra, the metals are meticulously and elaborately processed to oxides, salts and ashes that do not have the same biological activity as the more active, unprocessed compounds. Experienced practitioners of ayurveda assert that "heavy metals are integral to some formulations and have been used for centuries. There is no point of doing trials as they have been used safely and have mention in our ancient texts." In addition, tens of thousands of patients are using the Rasa Shastra formulations in clinical settings in India under supervision and show no deleterious clinical effects. Vaidyas assert there are four main problems with the heavy metals issue: 1) manufacturers are often taking short-cuts in production for profit incentives, 2) there are adulterants in the products due to environmental contamination, 3) modern medical doctors are not well-versed in medicinal chemistry and the methodology known for testing bioavailability in Rasa Shastra, 4)there are too many other sources of heavy metals in modern patients that are not being identified, such as hair dyes, eye makeup, medical preservatives, and occupational exposures.

There is a technique of detoxification applied to heavy metals and toxic herbs called samskaras, which is similar to the Chinese pao zhi although the Ayurvedic technique is more complex and may involve prayers as well as physical pharmacy techniques.

The described detoxification is a simple chemical process which involves four successive rounds of boiling the crude Aconitum root in cow's urine (twice) and cow's milk (twice). This process is claimed to chemically modify both toxic and proposed therapeutic components of the root. It also extracts some of these compounds from the root into the boiling solvents, thereby decreasing their concentration in the final product.