Ayurveda

• 1. Introduction

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  Ayurveda holds that sneezing should not be suppressed, because to do so might give rise to shoulder pain. That one idea, precise and strange in equal measure, opens a window onto a medical tradition that has been shaping how hundreds of millions of people understand their own bodies for more than two thousand years. As much as 80 percent of the population of India and Nepal report using ayurveda, making it one of the most widely practiced healing systems on earth. And yet its foundational premises are not based on science, its pharmacopoeia contains preparations laced with lead, mercury, and arsenic, and the global market built around it was valued at US$4.5 billion in 2017. How does a system that ancient, that contested, and that consequential still hold such a grip? The answer runs through Vedic sages and Renaissance surgeons, through a Sanskrit term meaning "knowledge of longevity," and through a very modern argument about what counts as medicine at all.

• 2. Knowledge of Longevity

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  The Sanskrit word āyurveda joins āyus, meaning "life" or "longevity," with veda, meaning "knowledge." The phrase first carried real clinical weight in the Mahābhārata, dated to around the 4th century BCE, which describes medicine as having eight components. Those eight branches range from general medicine of the body to pediatrics, surgery, toxicology, and what the tradition calls Bhūtavidyā, the pacification of possessing spirits in people whose minds are affected by them. The breadth is striking. Śalyatantra covered surgical techniques and the extraction of foreign objects. Rasāyantantra addressed rejuvenation and tonics for increasing lifespan, intellect, and strength. Vājīkaraṇatantra dealt with aphrodisiacs, fertility, and the volume and viability of semen.

  The main surviving texts are three works: the Charaka Samhita, the Sushruta Samhita, and the Bhela Samhita. Non-specialist scholars have long placed these in the 6th century BCE, but medical historians of South Asia now date them, in their present forms, to between the 2nd and 5th centuries CE. The Sushruta Samhita, for instance, is understood to have begun with a kernel of medical ideas from around one or two centuries BCE, then been revised by multiple hands into its final shape by roughly 500 CE. Printed editions frame the work as the teachings of Dhanvantari, the Hindu deity of ayurveda, incarnated as King Divodāsa of Varanasi. The oldest surviving manuscripts, however, omit that divine framing entirely and attribute the work directly to King Divodāsa himself.

  The texts describe the body as built from seven tissues, called dhatus: chyle, blood, muscles, fat, bone, marrow, and semen. Alongside these tissues run channels called srotas, which transport fluids, and can be opened through massage using oils and a warming treatment called Swedana. Blocked or unhealthy channels are held to cause disease. The tradition also identifies twenty qualities, organized into ten pairs, that are considered inherent in all matter: heavy and light, cold and hot, unctuous and dry, dull and sharp, stable and mobile, and so on through to viscous and liquid.

• 3. The Three Doshas

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  Vata, pitta, and kapha are the three elemental humors at the center of ayurvedic theory, and they touch nearly everything in the tradition: diagnosis, prescription, personality, and the definition of disease itself. Vata is linked to air and, by some modern commentators, to the nervous system. Pitta is associated with bile and fire, equated by some writers with enzymes. Kapha corresponds to phlegm and to the elements of earth and water, compared by some to mucus. Contemporary critics argue that the doshas are not real and are a fictional concept.

  The balance of these three humors, called sāmyatva in Sanskrit, is described as health. Imbalance, viṣamatva, produces disease. One view within the tradition holds that the doshas are balanced when equal; another holds that each person possesses a unique combination that defines their constitution, called prakriti. Practitioners must determine a patient's dosha makeup because certain prakriti are said to predispose a person to particular diseases. A person described as thin, shy, excitable, with a pronounced Adam's apple and an interest in esoteric knowledge is likely of vata prakriti and, by that logic, more susceptible to flatulence, stuttering, and rheumatism.

  The Charaka Samhita takes dosha imbalance further, attributing "insanity" (unmada) not only to excess vayu, meaning gas, but also to cold food and to possession by the ghost of a sinful Brahman, specifically a brahmarakshasa. The concept of ama, from a Sanskrit word meaning "uncooked" or "undigested," describes anything in a state of incomplete transformation. With regard to oral hygiene, ama is claimed to be a toxic byproduct of improper digestion. No equivalent concept exists in standard medicine.

• 4. Surgery, Rhinoplasty, and the Surgeon's Art

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  Two of the eight classical branches of ayurveda deal directly with surgery, and the tradition's surgical legacy eventually traveled far beyond India. Underwood and Rhodes document that early ayurvedic practice recognized plastic surgery, lithotomy, tonsillectomy, a form of cataract surgery called couching, puncturing to release abdominal fluids, extraction of foreign bodies, treatment of anal fistulas, amputations, cesarean sections, and the stitching of wounds. Treatments were also prescribed for angina pectoris, diabetes, hypertension, and kidney stones.

  Rhinoplasty is the operation that left the clearest mark on Western medicine. British physicians living in India observed the procedure being performed using Indian methods, and reports appeared in London in the Gentleman's Magazine in 1794. Joseph Constantine Carpue spent twenty years studying plastic surgery in India, and in 1815 he performed the first major rhinoplasty surgery in the Western world using what was called the "Indian" method. In 1840, Brett published a further article on the technique. Surgical instruments described in the Sushruta Samhita were also modified in Europe. In Renaissance Italy, the Branca family of Sicily and Gaspare Tagliacozzi of Bologna were both influenced by the Arabic transmission of Sushruta's techniques.

  That Arabic connection came through an earlier chain of translation. The medical works of Sushruta and Charaka were first rendered into Chinese in the 5th century, then into Arabic and Persian during the 8th century. The 9th-century Persian physician Muhammad ibn Zakariya al-Razi was familiar with those texts. Arabic works derived from the ayurvedic originals reached Europe by the 12th century, creating a thread of surgical knowledge that ran from ancient India to Renaissance operating rooms.

• 5. Toxic Metals and Rasashastra

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  Minerals began entering the ayurvedic pharmacopoeia more pervasively after the 11th century, under the influence of early Indian alchemy, a practice called rasashastra. The term describes adding metals, minerals, or gems to herbal preparations, and the substances prescribed include sulfur, arsenic, lead, copper sulfate, and gold. Advocates hold that physico-chemical purification processes, called samskaras or shodhanas, detoxify the heavy metals. Critics, including public health researchers, have accumulated a damaging body of evidence against that claim.

  A 1990 study of ayurvedic medicines in India found that 41 percent of products tested contained arsenic, and that 64 percent contained lead and mercury. A 2004 study found toxic levels of heavy metals in 20 percent of ayurvedic preparations made in South Asia and sold in the Boston area. A 2008 study of more than 230 products found that approximately 20 percent of remedies, and 40 percent of rasashastra medicines specifically, purchased over the internet from U.S. and Indian suppliers, contained lead, mercury, or arsenic. Between 1978 and 2008, more than 80 cases of lead poisoning associated with ayurvedic medicine use were reported worldwide. In 2012, the U.S. Centers for Disease Control and Prevention linked ayurvedic drugs to lead poisoning, based on cases where toxic materials appeared in the blood of pregnant women who had taken ayurvedic preparations.

  A 2015 study of users in the United States found elevated blood lead levels in 40 percent of those tested. Physician and former U.S. Air Force flight surgeon Harriet Hall described ayurveda in response as "basically superstition mixed with a soupçon of practical health advice. And it can be dangerous." A 2022 study of over-the-counter preparations purchased in Chandigarh, India, found that 83 percent exceeded WHO and FAO limits for zinc, 69 percent for mercury, 14 percent for arsenic, and 5 percent for lead. The infant digestive product ghasard has been found to contain up to 1.6 percent lead by weight, leading to documented cases of lead encephalopathy. In 2023, the Victorian Department of Health in Australia issued a health advisory warning that unregulated ayurvedic products sold in the state may contain unsafe levels of all three metals, as well as harmful compounds from the plants Azadirachta indica and Acorus calamus.

  In India, the government has required that ayurvedic products be labeled with their metallic content, but M. S. Valiathan, writing in the Indian Academy of Sciences publication Current Science, noted that the absence of post-market surveillance and the shortage of testing facilities made quality control exceedingly difficult. In the United States, most ayurvedic products have been marketed without FDA review or approval, though since 2007 the agency has placed an import alert on some products to prevent them from entering the country.

• 6. Going West

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  Baba Hari Dass arrived as an early and formative figure in bringing ayurveda to the United States in the early 1970s. His work led to the establishment of the Mount Madonna Institute, and he invited notable ayurvedic teachers including Vasant Lad, Sarita Shrestha, and Ram Harsh Singh. The ayurvedic practitioner Michael Tierra later wrote that "the history of Ayurveda in North America will always owe a debt to the selfless contributions of Baba Hari Dass."

  Maharishi Ayurveda extended the system's reach through the 1980s. The first ayurvedic clinic in Switzerland was opened in 1987 by Maharishi Mahesh Yogi. By 2015, the Swiss government had introduced a federally recognized diploma in ayurveda. As of 2018, the National Center for Complementary and Integrative Health in the United States reported that 240,000 Americans were using ayurvedic medicine, while also stating that "few well-designed clinical trials and systematic research reviews suggest that Ayurvedic approaches are effective."

  Scholars who study the global spread of the tradition distinguish between "modern ayurveda" and "global ayurveda." Modern ayurveda, centered in the Indian subcontinent, tends toward secularization by minimizing the magical and mythical elements of the tradition. Global ayurveda, practiced across a wide geographical area outside India, encompasses several strands: those primarily interested in the pharmacopoeia, practitioners of New Age ayurveda linking the system to yoga and Indian spirituality, and followers of Maharishi ayurveda itself. The government of India established the Ministry of Ayush on the 9th of November 2014, and National Ayurveda Day is observed each year on Dhanteras, the birth date of Dhanvantari. The global ayurveda market reached US$4.5 billion in 2017, a figure that reflects both the system's commercial momentum and the scale of its unresolved safety questions.