Ayurveda is a system of medicine with historical roots in the Indian subcontinent. Globalized and modernized practices derived from Ayurveda traditions are a type of complementary or alternative medicine.In the Western world, Ayurveda therapies and practices (which are manifold) have been integrated in general wellness applications and as well in some cases in medical use. The main classical Ayurveda treatises begin with legendary accounts of the transmission of medical knowledge from the Gods to sages, and thence to human physicians. Thus, the Sushruta Samhita narrates how Dhanvantari, "greatest of the mighty celestial," incarnated himself as Divodāsa, a mythical king of Varanasi, who then taught medicine to a group of wise physicians, including Sushruta himself.Ayurveda therapies have varied and evolved over more than two millennia.Therapies are typically based on complex herbal compounds, while treatises introduced mineral and metal substances (perhaps under the influence of early Indian alchemy or rasaśāstra). Ancient Ayurveda treatises also taught surgical techniques, including rhinoplasty, perineal lithotomy, the suturing of wounds, and the extraction of foreign objects. Although laboratory experiments suggest it is possible that some substances in Ayurveda might be developed into effective treatments, there is no evidence that any are effective as currently proffered. Ayurveda medicine is considered pseudoscientific. Other researchers consider it a protoscience, or trans-science system instead. Close to 21% of Ayurveda U.S. and Indian-manufactured patent medicines sold through the Internet were found to contain toxic levels of heavy metals, specifically lead, mercury, and arsenic. The public health implications of such metallic contaminants in India are unknown.
Plant-based treatments in Ayurveda may be derived from roots, leaves, fruits, bark, or seeds such as cardamom and cinnamon. In the 19th century, William Dymock and co-authors summarized hundreds of plant-derived medicines along with the uses, microscopic structure, chemical composition, toxicology, prevalent myths and stories, and relation to commerce in British India. Animal products used in Ayurveda include milk, bones, and gallstones. In addition, fats are prescribed both for consumption and for external use. Consumption of minerals, including sulphur, arsenic, lead, copper sulfate and gold, are also prescribed. The addition of minerals to herbal medicine is called rasa shastra. Ayurveda uses alcoholic beverages called Madya, which are said to adjust the doshas by increasing Pitta and reducing Vatta and Kapha. Madya are classified by the raw material and fermentation process, and the categories include: sugar-based, fruit-based, cereal-based, cereal-based with herbs, fermentated with vinegar, and tonic wines. The intended outcomes can include causing purgation, improving digestion or taste, creating dryness, or loosening joints. Ayurvedic texts describe Madya as non-viscid and fast-acting, and say that it enters and cleans minute pores in the body. Purified opium is used in eight Ayurvedic preparations and is said to balance the Vata and Kapha doshas and increase the Pitta dosha. It is prescribed for diarrhea and dysentery, for increasing the sexual and muscular ability, and for affecting the brain. The sedative and pain-relieving properties of opium are not considered in Ayurveda. The use of opium is not found in the ancient Ayurvedic texts, and is first mentioned in the Sarngadhara Samhita (1300-1400 CE), a book on pharmacy used in Rajasthan in Western India, as an ingredient of an aphrodisiac to delay male ejaculation. It is possible that opium was brought to India along with or before the Mohammedan conquest. The book Yoga Ratnakara (1700-1800 CE, unknown author), which is popular in Maharashtra, uses opium in a herbal-mineral composition prescribed for diarrhea. In the Bhaisajya Ratnavali, opium and camphor are used for acute gastroenteritis. In this drug, the respiratory depressant action of opium is counteracted by the respiratory stimulant property of Camphor. Later books have included the narcotic property for use as analgesic pain reliever. Cannabis indica is also absent from the ancient Ayurveda books, and is first mentioned in the Sarngadhara Samhita as a treatment for diarrhea. In the Bhaisajya Ratnavali it is named as an ingredient in an aphrodisiac.