Safety of Ayurvedic Medicine

The use of toxic herbs and of toxic metals and minerals as ingredients in traditional ayurvedic treatments is a major safety concern. Rasa shastra, the practice of adding metals, minerals or gems to herbs, is a source of toxic heavy metals such as lead, mercury and arsenic. Adverse reactions to herbs due to their pharmacology are described in traditional ayurvedic texts, but ayurvedic practitioners are reluctant to admit that herbs could be toxic and the reliable information on herbal toxicity is not readily available.

A 2004 study found such toxic metals in 20% of ayurvedic preparations that were made in South Asia for sale around Boston and extrapolated the data to the United States more broadly. It concluded that excess consumption of these products could cause health risks. A 2008 study of more than 230 products found that approximately 20% of remedies (and 40% of rasa shastra medicines) purchased over the Internet from both US and Indian suppliers contained lead, mercury or arsenic. Traditionally the toxicity of these materials are believed to be reduced through purification processes such as samskaras or shodhanas (for metals), 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. One medical journal reported:

"Crude aconite is an extremely lethal substance, yet ayurveda looks upon it as a therapeutic entity. Crude aconite is always processed, i.e. it undergoes 'samskaras' before being utilised in the Ayurvedic formulations. This study was undertaken in mice, to ascertain whether "processed" aconite is less toxic as compared to the crude or unprocessed one. It was seen that crude aconite was significantly toxic to mice (100% mortality at a dose of 2.6 mg/mouse) whereas the fully processed aconite was absolutely non-toxic (no mortality at a dose even 8 times as high as that of crude aconite). Further, all the steps in the processing were essential for complete detoxification. "

Rigorous evidence that the metals may be rendered nontoxic is not available, and case reports describe adverse effects of these metals. Following concerns about metal toxicity, the Government of India ruled that ayurvedic products must specify their metallic content directly on the labels of the product.The harmful effects of the samples is attributed in part to the adulterated raw material and lack of workers trained in traditional medicine. In a letter to the Indian Academy of Sciences, director of the Interdisciplinary School of Health Sciences, University of Pune Patwardhan Bhushan stated that the metal adulteration is due to contamination and carelessness during the much faster modern manufacturing processes, and does not occur with traditional methods of preparation.