Rasa Shastra

Metal medicines and alchemy in medieval India

A critical review of the Rasaratna Samuccaya states that metal and mineral medicines entered Ayurveda in the medieval period, that the exact start is difficult to establish, and that their use perhaps grew from the sixth century CE and took about another century to become the discipline called Rasashastra. The review gives the original aim as dehavada, a long and healthy life through preparations of mercury and other metals, with lohavada, the conversion of lower metals into gold and silver, pursued later.

A World Health Organization document on Ayurveda training makes a similar broad statement. It says that between the eighth and sixteenth centuries Ayurveda was enriched by the development of chemistry (rasasastra), and that advances in chemistry brought techniques to detoxify metals and minerals and to compound mineral and herbo-mineral formulations.

Texts and their dating

The Rasaratna Samuccaya is described in that review as a thirteenth-century compilation attributed to Vagbhata, with 30 chapters, 3871 verses and 960 formulations. The review places the Rasarnava in the eighth century and the Rasendra Mangala and Rasendracudamani in the eleventh and twelfth centuries, and names Nagarjuna as an eighth-century figure. It also reports that the compiler worships Shiva as the originator of Rasashastra and advises that the knowledge be kept secret. Dates for these texts rest on that one review and may be given differently elsewhere.

Disagreement about how old the practice is

Sources differ on antiquity. A chemical analysis of twenty bhasmas states that these preparations have been known in the Indian subcontinent since the seventh century BC, while the Rasaratna Samuccaya review suggests metal medicines gained momentum from about the sixth century CE. The sources reviewed do not reconcile the two statements, and this page does not treat either as established.

Rasa Shastra and its aims

Authors from the discipline describe Rasashastra as the study of mercury together with a number of metals, minerals, gems and plant and animal products. In this usage rasa refers to mercury, and the term is often glossed as Ayurvedic alchemy. Other reviewers describe it as the process of imparting medicinal value to minerals. Within the literature the products are called herbo-mineral or herbo-metallic preparations, because metals and minerals are combined with plant or animal materials.

Bhasma, shodhana and marana

Bhasma means an ash prepared from a metal or mineral. A review of the Ayurvedic metals literature lists mercury (Parada), gold (Swarna), silver (Rajata), copper (Tamra), iron (Lauha), tin (Vanga), lead (Naga) and zinc (Yasada) as metals used in incinerated bhasma form. Reviewers use shodhana for purification and marana for calcination, and describe bhasmas as processed with herbal juices or decoctions and animal-based materials and repeatedly incinerated. This page names these terms only and does not describe procedures.

Related Machipedia pages

Rasa Shastra belongs to the wider system covered on the Machipedia page named Ayurveda. Ayurvedic Herbal Medicine and Herbal Medicine cover plant-based remedies, and findings reported here about metal-containing preparations should not be carried over to plant-only products. Reviewers describe the tradition's elixir ideal as the capacity to give perpetual life, and Rasayana Therapy is the page for the longevity tradition more broadly.

What the preparations are in general terms

A review of bhasmas and the related Tibetan preparation Zuotai states that the metals found in Ayurvedic medicines come mainly from intentional addition in bhasma form, that minerals are not used alone but in mixtures with herbal or animal-based materials, and that the processed products are described as having smaller particle sizes. It quotes experts who estimate that 35 to 40 percent of Ayurvedic medicines contain at least one metal, and notes that minerals account for about 8 percent of the Ayurvedic Pharmacopoeia of India.

A laboratory analysis of twenty bhasmas found major constituents based on calcium, iron, zinc, mercury, silver, potassium, arsenic, copper and tin, plus gemstone-based products. The authors describe the products as biologically produced nanoparticles. The study reports elemental composition and does not report outcomes in people.

Training and restricted knowledge

The World Health Organization benchmarks for Ayurveda training list preparation and storage of mineral and herbo-mineral drugs (rasasastra) among the knowledge expected of practitioners, and list safety issues and dosages related to mineral-based medicines in the training of basic-level Ayurveda pharmacists. The Rasaratna Samuccaya review adds that the classical author advised keeping this knowledge secret, which is one reason this page describes the field by name and does not reproduce technical detail.

Uses attributed to classical texts

The Rasaratna Samuccaya review reports that the text emphasizes the use of metals and minerals in treating nearly 68 types of ailments. A review of the Ayurvedic metals literature states that the classics describe the pharmacological actions, therapeutic indications and adverse effects of each metal, with attention to preparation, dose and duration. A review of lead-based preparations reports that Naga bhasma has traditionally been used in India for diabetes, spleen enlargement, diarrhea and skin diseases. These are statements of what texts and authors hold, and they are not findings from controlled studies.

Reasons given for using processed metals

Authors cite better stability, lower dosage, ease of storage and sustained availability as advantages of herbo-mineral preparations, and describe the traditional belief that elaborate processing modifies the toxic nature of the starting metal. Other reviewers propose that low doses of processed metals could act through hormesis, in which small amounts are beneficial and large amounts harmful. These are hypotheses offered by the reviewers, not established mechanisms.

Clinical research

A 2019 review of bhasmas states that detailed publications on well-designed clinical trials are not easily found. PubMed searches run for this page on herbo-mineral and bhasma safety, and on Rasashastra, retrieved laboratory studies, animal studies, case reports and narrative reviews, and did not retrieve a systematic review of clinical efficacy or safety. Evidence for one preparation or one condition should not be carried to other preparations or conditions.

Laboratory and animal findings

In one rat study of a mica-based bhasma, a single high dose caused no deaths or visible adverse effects, and the authors classified it in the lowest hazard category of the Globally Harmonized System. In 28-day repeated dosing, the low dose, extrapolated from the highest clinical dose, did not cause toxicity, while the middle and high doses caused dose-dependent liver toxicity that was reversible. The authors state that this shows the importance of careful dose consideration and patient monitoring. Animal results do not establish effects in people.

The 2019 review summarizes animal studies in which processed forms such as cinnabar and some bhasmas led to lower tissue accumulation and less toxicity than environmental forms such as mercuric chloride, and reports that unprocessed or incompletely processed materials were more toxic in some experiments. It presents these as reasons to question risk assessment by total metal content. The page has not verified each underlying study.

Contamination surveys of products

A 2004 survey of 70 Ayurvedic products made in South Asia and sold in Boston-area stores found heavy metals in 14 (20 percent): lead in 13, mercury in 6 and arsenic in 6. The authors estimated that each of the 14 could give intakes above published standards if used as the manufacturers recommended. This page read the abstract only.

A 2008 study analyzed 193 Ayurvedic medicines bought from internet sellers and found detectable lead, mercury or arsenic in 20.7 percent, at similar rates in US-made and Indian-made products. Rasa shastra products more often contained metals than other products (40.6 versus 17.1 percent), and all metal-containing products exceeded at least one daily-intake standard.

Contested claims about safety

Authors disagree. A review of the lead-based preparation Naga bhasma states that no compelling evidence has been put forward of toxic manifestations of Naga bhasma itself, while noting that elemental analysis of preparations containing it has shown extremely high lead content and that safety is hard to assure because most traditional medicines have no known molecular targets. The 2019 review argues that the chemical form of a metal, not its total content, determines toxicity, and that poisoning cases come mainly from inappropriate use and inappropriate preparation.

The two product surveys above measured metal content with X-ray fluorescence and compared estimated intakes with standards for lead, mercury and arsenic. They report what was detected, and the sources reviewed do not report the chemical form.

Case reports and clusters

Case reports describe serious lead poisoning. A Wisconsin report describes a woman aged 64 with anemia and a blood lead level of 85.8 micrograms per deciliter after using internet-bought Ayurvedic products. An Italian report describes a sailor with a level of 102 whose two products included one with very high lead and mercury. A neurology report describes two women with lead encephalopathy after long-term Ayurvedic medication, one of whom died. Chelation was used in the first two; see Chelation Therapy, a hospital treatment for poisoning and not a use of Rasa Shastra.

A screening of 115 members of a US Ayurvedic community found that 46 (40 percent) had blood lead levels of 10 micrograms per deciliter or above, and 9.6 percent had levels of 50 or above. The authors call it the largest US cluster of its kind reported.

Arsenic and mercury

Authors describe arsenic poisoning from Ayurvedic medication as rarer than lead poisoning. A report of three patients found high arsenic in blood, urine, hair and nails, and in the medication for two. All recovered after the medication was stopped and a chelator given, and the authors say it is unclear whether stopping alone would have sufficed.

Pregnancy, children, kidney disease and other groups

A New York City health department report investigated six cases of lead poisoning in foreign-born pregnant women who used ten oral Ayurvedic medications made in India, with blood lead levels of 16 to 64 micrograms per deciliter. It states that fetal lead exposure can impair neurodevelopment and fetal growth and raise the risk of premature birth and miscarriage.

Traditional sources differ. One review states the classics list no contraindications for bhasmas. A review of the Rasaratna Samuccaya notes that the text lists no metal in obstetric or pediatric formulations and reads this as advice against use in pregnancy and children. A 2019 review calls childhood a vulnerable period for metal toxicity. The sources reviewed give no guidance specific to kidney disease; individual advice from a qualified clinician is needed.

Published guidance, training and care boundaries

The US National Center for Complementary and Integrative Health states that some Ayurvedic preparations may contain toxic amounts of lead, mercury or arsenic, advises against using Ayurvedic medicine to postpone conventional care, advises pregnant or nursing women to consult a provider, and notes that Ayurvedic practice and education are not significantly regulated in the United States.

The World Health Organization training benchmarks include medicines containing metals, minerals or poisonous substances in practitioner safety content and describe pharmacovigilance reporting of adverse reactions. They set training categories and do not certify any practitioner or product. Metal-containing products should not replace or delay necessary medical care.