The Bṛhat-Trayī, literally translated as "The Great Triad (Of Compositions)", refers to three early Sanskrit encyclopaedias of medicine, which are the core texts of the indigenous Indian medical system of Ayurveda.
These are contrasted with the Laghu-Trayī or the "lesser triad", a secondary set of later authoritative compositions.
It was first devised probably at some time in the early twentieth century, although its earliest use has not yet (2024) been identified.
There are older, authoritative medical encyclopaedias that are not included in the Bṛhat-Trayī, for example the Bheḷa-saṃhitā.
All three works have been published in numerous Sanskrit editions, and all have been translated into English more than once.