Whereas Ayurveda is the principal component of traditional Indian medicine, the latter includes Siddha medicine (a totally different system practised principally in Tamil Nadu and using different herbs), Unnani (Greek) medicine, Tibetan medicine and tribal medicines. Ayurveda is a 3000-year-old northern tradition that continued to evolve until the end of the Indian classical period in the sixth century. Its main objectives are to promote quality of life and longevity. Four rare, terrestrial orchid species are included in the preparation of Asthavarga, which is both tonic and aphrodisiac. Today, over 100 orchid species are used in Indian traditional medicine, but for many of them there is disagreement among herbalists as to whether some were also those mentioned in early texts because descriptions in such texts are not botanically precise. Siddha medicine is practised in the Tamil-speaking region of India. Siddhas are holy men with intuitive/divine knowledge and Siddha medicine is attributed to the god Shiva who transmitted it to Agasthiar. Siddha medicine is not entirely the provenance of siddhas; it is also practised by learned folk and grandmothers. There are 2000 drugs listed but only around 300 are in contemporary usage.
Herbal usage in Persian and Arab medicine is based on the work of Avicenna (Ibn Sina, 980-1037), who was strongly influenced by Dioscorides and other Greek physicians. In Iran, approximately six million orchid plants of 16 species are harvested for salep, once a much-touted aphrodisiac. Orchids are also used in Thai, Malay and Indonesian folk medicine.