Charaka

'Charaka' may refer to a single redactor or to a wandering school of physicians (the word relates to car-, 'to wander') who compiled and transmitted a shared body of medical knowledge, ultimately fixed in something close to its present form around the 2nd century CE, though drawing on much older material. As with several ancient Indian scientific texts, the authorship question matters less than the coherence of the system the text describes.

The Charaka Saṃhitā's central diagnostic model organises bodily function around three doṣas — vāta (movement), pitta (transformation/metabolism), and kapha (structure/cohesion) — whose balance or imbalance is held to determine health. Diagnosis proceeds by identifying which doṣa is disturbed and by how much, and treatment aims to restore equilibrium through diet, herbal preparation, and regimen rather than treating a symptom in isolation. It is a holistic system in the literal sense: the text explicitly connects digestion, metabolism, immunity, and mental state as expressions of the same underlying balance.

The Saṃhitā includes an explicit ethical code for physicians — sometimes called the Charaka Oath — covering conduct toward patients, confidentiality, the physician's obligation to keep studying, and the refusal to treat for improper motives. It sits alongside the (later, separately transmitted) Hippocratic tradition as one of the ancient world's earliest attempts to formalise medical ethics as a professional discipline rather than leaving it to individual conscience.

Unlike many texts on this list, Ayurveda built on Charaka's framework remains in active clinical practice today, alongside — and increasingly in dialogue with — biomedical medicine. The Saṃhitā's attention to constitutional variation between patients (prakṛti), a concept with a loose family resemblance to later ideas about individual physiological difference and heredity, keeps it a live reference point rather than a purely historical curiosity.