Ayurveda (Sanskrit: आयुर्वेद Āyurveda , "life-knowledge") or Ayurvedic medicine is a system of medicine with historical roots in the Indian subcontinent. Globalized and modernized practices derived from Ayurvedic traditions are a type of alternative medicine. In medieval taxonomies of the Sanskrit knowledge systems, Ayurveda is assigned a place as a subsidiary Veda (upaveda). Some medicinal plant names from the Atharvaveda and other Vedas can be found in subsequent Ayurveda literature. The earliest recorded theoretical statements about the canonical models of disease in Ayurveda occur in the earliest Buddhist Canon.
The main classical Ayurvedic 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 celestials," incarnated himself as Divodāsa, a mythical king of Varanasi, who then taught medicine to a group of wise physicians, including Sushruta himself. Ayurvedic therapies have varied and evolved over more than two millennia. Therapies are typically based on complex herbal compounds, while treatises written after about 1000 CE introduced mineral and metal substances (perhaps under the influence of early Indian alchemy or rasaśāstra). Ancient Ayurvedic treatises also taught surgical techniques, including rhinoplasty, perineal lithotomy, the suturing of wounds, and the extraction of foreign objects.
Some scholars assert that Ayurveda originated in prehistoric times, and that some of the concepts of Ayurveda have been discovered since the times of Indus Valley Civilization and earlier. Ayurveda significantly developed during the Vedic period and later some of the non-Vedic systems such as Buddhism and Jainism also developed medical concepts and practices that appear in the classical Ayurvedic treatises. Humoral balance is emphasized, and suppressing natural urges is considered unhealthy and claimed to lead to illness. Ayurveda names three elemental substances, the doshas (called Vata, Pitta and Kapha), and states that a balance of the doshas results in health, while imbalance results in disease. Ayurveda has eight canonical components, which are derived from classical Sanskrit literature. Some of the oldest known Ayurvedic texts include the Suśrutha Sahitā and Charaka Sahitā, which are written in Sanskrit. Ayurvedic practitioners had developed various medicinal preparations and surgical procedures by the medieval period.