Ayurveda (Sanskrit: आयुर्वेद; Āyurveda, "the knowledge for long life"; /ˌaɪ.ərˈveɪdə/) or ayurvedic medicine is a Hindu system of traditional medicine native to India and a form of alternative medicine. The earliest literature on Indian medical practice appeared during the Vedic period in India, i.e., in the mid-second millennium BCE. The Suśruta Saṃhitā and the Charaka Saṃhitā, encyclopedias of medicine compiled from various sources from the mid-first millennium BCE to about 500 CE, are among the foundational works of Ayurveda. Over the following centuries, ayurvedic practitioners developed a number of medicinal preparations and surgical procedures for the treatment of various ailments. Current practices derived (or reportedly derived) from Ayurvedic medicine are regarded as part of complementary and alternative medicine. Safety concerns have been raised about Ayurveda, with two U.S. studies finding about 20 percent of Ayurvedic Indian-manufactured patent medicines contained toxic levels of heavy metals such as lead, mercury and arsenic. Other concerns include the use of herbs containing toxic compounds and the lack of quality control in Ayurvedic facilities. At an early period[when?], Ayurveda adopted the physics of the "five elements" (Devanāgarī: [महा] पञ्चभूत); earth (Pṛthvī), water (Jala), fire (Agni), air (Vāyu) and space (Ākāśa) that compose the universe, including the human body. Ayurveda describes seven types of tissues of the body, known as thesaptadhātu (Devanāgarī: सप्तधातु). They are plasma (rasa dhātu), blood (rakta dhātu), flesh (māṃsa dhātu), adipose (medha dhātu), bone (asthi dhātu),marrow and nervous (majja dhātu), and reproductive (semen or female reproductive tissue) (śukra dhātu). Ayurvedic literature deals elaborately with measures of healthful living during the entire span of life and its various phases. Ayurveda stresses a balance of three elemental energies or humors:Vāyu / vāta (air & space – "wind"), pitta (fire & water – "bile") and kapha (water & earth – "phlegm"). According to ayurvedic medical theory, these three substances — doṣas (Devanāgarī: दोष)—are important for health, because when they exist in equal quantities, the body will be healthy, and when they are not in equal amounts, the body will be unhealthy in various ways. One ayurvedic theory asserts that each human possesses a unique combination of doṣas that define that person's temperament and characteristics. Another view, also present in the ancient literature, asserts that humoral equality is identical to health, and that persons with preponderances of humours are proportionately unhealthy, and that this is not their natural temperament. In ayurveda, unlike the Sāṅkhya philosophical system, there are 20 fundamental qualities, guṇa (Devanāgarī: गुण, meaning qualities) inherent in all substances. While surgery and surgical instruments were employed from a very early period, Ayurvedic theory asserts that building a healthy metabolic system, attaining good digestion, and proper excretion lead to vitality. Ayurveda also focuses on exercise, yoga, and meditation. The practice of panchakarma (Devanāgarī: पंचकर्म) is a therapeutic way of eliminating toxic elements from the body. As early as the Mahābhārata, ayurveda was called "the science of eight components" (Skt. aṣṭāṅga, Devanāgarī: अष्टांग), a classification that became canonical for ayurveda. They are: 1. Internal medicine (Kāya-cikitsā)
2. Paediatrics (Kaumārabhṛtyam)
3. Surgery (Śalya-cikitsā)
4. Opthalmology and ENT (Śālākya tantra)
5. Psychiatry has been called Bhūta vidyā .
6. Toxicology (Agadatantram)
7. Prevention of diseases and improving immunity and rejuvenation (rasayana) 8. Aphrodisiacs and improving health of progeny (Vajikaranam) In Hindu mythology, the origin of ayurvedic medicine is attributed to Dhanvantari, the physician of the gods....